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mariadb/sql/item_cmpfunc.cc
Igor Babaev f1cc6dd401 Merge.
2011-03-12 05:14:10 -08:00

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/* Copyright (c) 2000, 2011, Oracle and/or its affiliates.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/**
@file
@brief
This file defines all compare functions
*/
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include "mysql_priv.h"
#include <m_ctype.h>
#include "sql_select.h"
static bool convert_constant_item(THD *, Item_field *, Item **);
static longlong
get_year_value(THD *thd, Item ***item_arg, Item **cache_arg,
Item *warn_item, bool *is_null);
static Item_result item_store_type(Item_result a, Item *item,
my_bool unsigned_flag)
{
Item_result b= item->result_type();
if (a == STRING_RESULT || b == STRING_RESULT)
return STRING_RESULT;
else if (a == REAL_RESULT || b == REAL_RESULT)
return REAL_RESULT;
else if (a == DECIMAL_RESULT || b == DECIMAL_RESULT ||
unsigned_flag != item->unsigned_flag)
return DECIMAL_RESULT;
else
return INT_RESULT;
}
static void agg_result_type(Item_result *type, Item **items, uint nitems)
{
Item **item, **item_end;
my_bool unsigned_flag= 0;
*type= STRING_RESULT;
/* Skip beginning NULL items */
for (item= items, item_end= item + nitems; item < item_end; item++)
{
if ((*item)->type() != Item::NULL_ITEM)
{
*type= (*item)->result_type();
unsigned_flag= (*item)->unsigned_flag;
item++;
break;
}
}
/* Combine result types. Note: NULL items don't affect the result */
for (; item < item_end; item++)
{
if ((*item)->type() != Item::NULL_ITEM)
*type= item_store_type(*type, *item, unsigned_flag);
}
}
/*
Compare row signature of two expressions
SYNOPSIS:
cmp_row_type()
item1 the first expression
item2 the second expression
DESCRIPTION
The function checks that two expressions have compatible row signatures
i.e. that the number of columns they return are the same and that if they
are both row expressions then each component from the first expression has
a row signature compatible with the signature of the corresponding component
of the second expression.
RETURN VALUES
1 type incompatibility has been detected
0 otherwise
*/
static int cmp_row_type(Item* item1, Item* item2)
{
uint n= item1->cols();
if (item2->check_cols(n))
return 1;
for (uint i=0; i<n; i++)
{
if (item2->element_index(i)->check_cols(item1->element_index(i)->cols()) ||
(item1->element_index(i)->result_type() == ROW_RESULT &&
cmp_row_type(item1->element_index(i), item2->element_index(i))))
return 1;
}
return 0;
}
/**
Aggregates result types from the array of items.
SYNOPSIS:
agg_cmp_type()
type [out] the aggregated type
items array of items to aggregate the type from
nitems number of items in the array
DESCRIPTION
This function aggregates result types from the array of items. Found type
supposed to be used later for comparison of values of these items.
Aggregation itself is performed by the item_cmp_type() function.
@param[out] type the aggregated type
@param items array of items to aggregate the type from
@param nitems number of items in the array
@retval
1 type incompatibility has been detected
@retval
0 otherwise
*/
static int agg_cmp_type(Item_result *type, Item **items, uint nitems)
{
uint i;
type[0]= items[0]->result_type();
for (i= 1 ; i < nitems ; i++)
{
type[0]= item_cmp_type(type[0], items[i]->result_type());
/*
When aggregating types of two row expressions we have to check
that they have the same cardinality and that each component
of the first row expression has a compatible row signature with
the signature of the corresponding component of the second row
expression.
*/
if (type[0] == ROW_RESULT && cmp_row_type(items[0], items[i]))
return 1; // error found: invalid usage of rows
}
return 0;
}
/**
@brief Aggregates field types from the array of items.
@param[in] items array of items to aggregate the type from
@paran[in] nitems number of items in the array
@details This function aggregates field types from the array of items.
Found type is supposed to be used later as the result field type
of a multi-argument function.
Aggregation itself is performed by the Field::field_type_merge()
function.
@note The term "aggregation" is used here in the sense of inferring the
result type of a function from its argument types.
@return aggregated field type.
*/
enum_field_types agg_field_type(Item **items, uint nitems)
{
uint i;
if (!nitems || items[0]->result_type() == ROW_RESULT )
return (enum_field_types)-1;
enum_field_types res= items[0]->field_type();
for (i= 1 ; i < nitems ; i++)
res= Field::field_type_merge(res, items[i]->field_type());
return res;
}
/*
Collects different types for comparison of first item with each other items
SYNOPSIS
collect_cmp_types()
items Array of items to collect types from
nitems Number of items in the array
skip_nulls Don't collect types of NULL items if TRUE
DESCRIPTION
This function collects different result types for comparison of the first
item in the list with each of the remaining items in the 'items' array.
RETURN
0 - if row type incompatibility has been detected (see cmp_row_type)
Bitmap of collected types - otherwise
*/
static uint collect_cmp_types(Item **items, uint nitems, bool skip_nulls= FALSE)
{
uint i;
uint found_types;
Item_result left_result= items[0]->result_type();
DBUG_ASSERT(nitems > 1);
found_types= 0;
for (i= 1; i < nitems ; i++)
{
if (skip_nulls && items[i]->type() == Item::NULL_ITEM)
continue; // Skip NULL constant items
if ((left_result == ROW_RESULT ||
items[i]->result_type() == ROW_RESULT) &&
cmp_row_type(items[0], items[i]))
return 0;
found_types|= 1<< (uint)item_cmp_type(left_result,
items[i]->result_type());
}
/*
Even if all right-hand items are NULLs and we are skipping them all, we need
at least one type bit in the found_type bitmask.
*/
if (skip_nulls && !found_types)
found_types= 1 << (uint)left_result;
return found_types;
}
static void my_coll_agg_error(DTCollation &c1, DTCollation &c2,
const char *fname)
{
my_error(ER_CANT_AGGREGATE_2COLLATIONS, MYF(0),
c1.collation->name,c1.derivation_name(),
c2.collation->name,c2.derivation_name(),
fname);
}
Item_bool_func2* Eq_creator::create(Item *a, Item *b) const
{
return new Item_func_eq(a, b);
}
Item_bool_func2* Ne_creator::create(Item *a, Item *b) const
{
return new Item_func_ne(a, b);
}
Item_bool_func2* Gt_creator::create(Item *a, Item *b) const
{
return new Item_func_gt(a, b);
}
Item_bool_func2* Lt_creator::create(Item *a, Item *b) const
{
return new Item_func_lt(a, b);
}
Item_bool_func2* Ge_creator::create(Item *a, Item *b) const
{
return new Item_func_ge(a, b);
}
Item_bool_func2* Le_creator::create(Item *a, Item *b) const
{
return new Item_func_le(a, b);
}
/*
Test functions
Most of these returns 0LL if false and 1LL if true and
NULL if some arg is NULL.
*/
longlong Item_func_not::val_int()
{
DBUG_ASSERT(fixed == 1);
bool value= args[0]->val_bool();
null_value=args[0]->null_value;
return ((!null_value && value == 0) ? 1 : 0);
}
/*
We put any NOT expression into parenthesis to avoid
possible problems with internal view representations where
any '!' is converted to NOT. It may cause a problem if
'!' is used in an expression together with other operators
whose precedence is lower than the precedence of '!' yet
higher than the precedence of NOT.
*/
void Item_func_not::print(String *str, enum_query_type query_type)
{
str->append('(');
Item_func::print(str, query_type);
str->append(')');
}
/**
special NOT for ALL subquery.
*/
longlong Item_func_not_all::val_int()
{
DBUG_ASSERT(fixed == 1);
bool value= args[0]->val_bool();
/*
return TRUE if there was records in underlying select in max/min
optimization (ALL subquery)
*/
if (empty_underlying_subquery())
return 1;
null_value= args[0]->null_value;
return ((!null_value && value == 0) ? 1 : 0);
}
bool Item_func_not_all::empty_underlying_subquery()
{
return ((test_sum_item && !test_sum_item->any_value()) ||
(test_sub_item && !test_sub_item->any_value()));
}
void Item_func_not_all::print(String *str, enum_query_type query_type)
{
if (show)
Item_func::print(str, query_type);
else
args[0]->print(str, query_type);
}
/**
Special NOP (No OPeration) for ALL subquery. It is like
Item_func_not_all.
@return
(return TRUE if underlying subquery do not return rows) but if subquery
returns some rows it return same value as argument (TRUE/FALSE).
*/
longlong Item_func_nop_all::val_int()
{
DBUG_ASSERT(fixed == 1);
longlong value= args[0]->val_int();
/*
return FALSE if there was records in underlying select in max/min
optimization (SAME/ANY subquery)
*/
if (empty_underlying_subquery())
return 0;
null_value= args[0]->null_value;
return (null_value || value == 0) ? 0 : 1;
}
/**
Convert a constant item to an int and replace the original item.
The function converts a constant expression or string to an integer.
On successful conversion the original item is substituted for the
result of the item evaluation.
This is done when comparing DATE/TIME of different formats and
also when comparing bigint to strings (in which case strings
are converted to bigints).
@param thd thread handle
@param field item will be converted using the type of this field
@param[in,out] item reference to the item to convert
@note
This function is called only at prepare stage.
As all derived tables are filled only after all derived tables
are prepared we do not evaluate items with subselects here because
they can contain derived tables and thus we may attempt to use a
table that has not been populated yet.
@retval
0 Can't convert item
@retval
1 Item was replaced with an integer version of the item
*/
static bool convert_constant_item(THD *thd, Item_field *field_item,
Item **item)
{
Field *field= field_item->field;
int result= 0;
if ((*item)->const_item())
{
TABLE *table= field->table;
ulong orig_sql_mode= thd->variables.sql_mode;
enum_check_fields orig_count_cuted_fields= thd->count_cuted_fields;
my_bitmap_map *old_maps[2];
ulonglong UNINIT_VAR(orig_field_val); /* original field value if valid */
LINT_INIT(old_maps[0]);
LINT_INIT(old_maps[1]);
if (table)
dbug_tmp_use_all_columns(table, old_maps,
table->read_set, table->write_set);
/* For comparison purposes allow invalid dates like 2000-01-32 */
thd->variables.sql_mode= (orig_sql_mode & ~MODE_NO_ZERO_DATE) |
MODE_INVALID_DATES;
thd->count_cuted_fields= CHECK_FIELD_IGNORE;
/*
Store the value of the field/constant if it references an outer field
because the call to save_in_field below overrides that value.
Don't save field value if no data has been read yet.
Outer constant values are always saved.
*/
bool save_field_value= (field_item->depended_from &&
(field_item->const_item() ||
!(field->table->status & STATUS_NO_RECORD)));
if (save_field_value)
orig_field_val= field->val_int();
if (!(*item)->is_null() && !(*item)->save_in_field(field, 1))
{
Item *tmp= new Item_int_with_ref(field->val_int(), *item,
test(field->flags & UNSIGNED_FLAG));
if (tmp)
thd->change_item_tree(item, tmp);
result= 1; // Item was replaced
}
/* Restore the original field value. */
if (save_field_value)
{
result= field->store(orig_field_val, TRUE);
/* orig_field_val must be a valid value that can be restored back. */
DBUG_ASSERT(!result);
}
thd->variables.sql_mode= orig_sql_mode;
thd->count_cuted_fields= orig_count_cuted_fields;
if (table)
dbug_tmp_restore_column_maps(table->read_set, table->write_set, old_maps);
}
return result;
}
void Item_bool_func2::fix_length_and_dec()
{
max_length= 1; // Function returns 0 or 1
THD *thd;
/*
As some compare functions are generated after sql_yacc,
we have to check for out of memory conditions here
*/
if (!args[0] || !args[1])
return;
/*
We allow to convert to Unicode character sets in some cases.
The conditions when conversion is possible are:
- arguments A and B have different charsets
- A wins according to coercibility rules
- character set of A is superset for character set of B
If all of the above is true, then it's possible to convert
B into the character set of A, and then compare according
to the collation of A.
*/
DTCollation coll;
if (args[0]->result_type() == STRING_RESULT &&
args[1]->result_type() == STRING_RESULT &&
agg_arg_charsets(coll, args, 2, MY_COLL_CMP_CONV, 1))
return;
args[0]->cmp_context= args[1]->cmp_context=
item_cmp_type(args[0]->result_type(), args[1]->result_type());
// Make a special case of compare with fields to get nicer DATE comparisons
if (functype() == LIKE_FUNC) // Disable conversion in case of LIKE function.
{
set_cmp_func();
return;
}
thd= current_thd;
if (!thd->lex->is_ps_or_view_context_analysis())
{
if (args[0]->real_item()->type() == FIELD_ITEM)
{
Item_field *field_item= (Item_field*) (args[0]->real_item());
if (field_item->field->can_be_compared_as_longlong() &&
!(field_item->is_datetime() &&
args[1]->result_type() == STRING_RESULT))
{
if (convert_constant_item(thd, field_item, &args[1]))
{
cmp.set_cmp_func(this, tmp_arg, tmp_arg+1,
INT_RESULT); // Works for all types.
args[0]->cmp_context= args[1]->cmp_context= INT_RESULT;
return;
}
}
}
if (args[1]->real_item()->type() == FIELD_ITEM)
{
Item_field *field_item= (Item_field*) (args[1]->real_item());
if (field_item->field->can_be_compared_as_longlong() &&
!(field_item->is_datetime() &&
args[0]->result_type() == STRING_RESULT))
{
if (convert_constant_item(thd, field_item, &args[0]))
{
cmp.set_cmp_func(this, tmp_arg, tmp_arg+1,
INT_RESULT); // Works for all types.
args[0]->cmp_context= args[1]->cmp_context= INT_RESULT;
return;
}
}
}
}
set_cmp_func();
}
int Arg_comparator::set_compare_func(Item_result_field *item, Item_result type)
{
owner= item;
func= comparator_matrix[type]
[is_owner_equal_func()];
switch (type) {
case ROW_RESULT:
{
uint n= (*a)->cols();
if (n != (*b)->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), n);
comparators= 0;
return 1;
}
if (!(comparators= new Arg_comparator[n]))
return 1;
for (uint i=0; i < n; i++)
{
if ((*a)->element_index(i)->cols() != (*b)->element_index(i)->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), (*a)->element_index(i)->cols());
return 1;
}
if (comparators[i].set_cmp_func(owner, (*a)->addr(i), (*b)->addr(i),
set_null))
return 1;
}
break;
}
case STRING_RESULT:
{
/*
We must set cmp_charset here as we may be called from for an automatic
generated item, like in natural join
*/
if (cmp_collation.set((*a)->collation, (*b)->collation) ||
cmp_collation.derivation == DERIVATION_NONE)
{
my_coll_agg_error((*a)->collation, (*b)->collation,
owner->func_name());
return 1;
}
if (cmp_collation.collation == &my_charset_bin)
{
/*
We are using BLOB/BINARY/VARBINARY, change to compare byte by byte,
without removing end space
*/
if (func == &Arg_comparator::compare_string)
func= &Arg_comparator::compare_binary_string;
else if (func == &Arg_comparator::compare_e_string)
func= &Arg_comparator::compare_e_binary_string;
/*
As this is binary compassion, mark all fields that they can't be
transformed. Otherwise we would get into trouble with comparisons
like:
WHERE col= 'j' AND col LIKE BINARY 'j'
which would be transformed to:
WHERE col= 'j'
*/
(*a)->walk(&Item::set_no_const_sub, FALSE, (uchar*) 0);
(*b)->walk(&Item::set_no_const_sub, FALSE, (uchar*) 0);
}
break;
}
case INT_RESULT:
{
if (func == &Arg_comparator::compare_int_signed)
{
if ((*a)->unsigned_flag)
func= (((*b)->unsigned_flag)?
&Arg_comparator::compare_int_unsigned :
&Arg_comparator::compare_int_unsigned_signed);
else if ((*b)->unsigned_flag)
func= &Arg_comparator::compare_int_signed_unsigned;
}
else if (func== &Arg_comparator::compare_e_int)
{
if ((*a)->unsigned_flag ^ (*b)->unsigned_flag)
func= &Arg_comparator::compare_e_int_diff_signedness;
}
break;
}
case DECIMAL_RESULT:
break;
case REAL_RESULT:
{
if ((*a)->decimals < NOT_FIXED_DEC && (*b)->decimals < NOT_FIXED_DEC)
{
precision= 5 / log_10[max((*a)->decimals, (*b)->decimals) + 1];
if (func == &Arg_comparator::compare_real)
func= &Arg_comparator::compare_real_fixed;
else if (func == &Arg_comparator::compare_e_real)
func= &Arg_comparator::compare_e_real_fixed;
}
break;
}
default:
DBUG_ASSERT(0);
}
return 0;
}
/**
Parse date provided in a string to a MYSQL_TIME.
@param[in] thd Thread handle
@param[in] str A string to convert
@param[in] warn_type Type of the timestamp for issuing the warning
@param[in] warn_name Field name for issuing the warning
@param[out] l_time The MYSQL_TIME objects is initialized.
Parses a date provided in the string str into a MYSQL_TIME object. If the
string contains an incorrect date or doesn't correspond to a date at all
then a warning is issued. The warn_type and the warn_name arguments are used
as the name and the type of the field when issuing the warning. If any input
was discarded (trailing or non-timestamp-y characters), return value will be
TRUE.
@return Status flag
@retval FALSE Success.
@retval True Indicates failure.
*/
bool get_mysql_time_from_str(THD *thd, String *str, timestamp_type warn_type,
const char *warn_name, MYSQL_TIME *l_time)
{
bool value;
int error;
enum_mysql_timestamp_type timestamp_type;
timestamp_type=
str_to_datetime(str->ptr(), str->length(), l_time,
(TIME_FUZZY_DATE | MODE_INVALID_DATES |
(thd->variables.sql_mode &
(MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE))),
&error);
if (timestamp_type == MYSQL_TIMESTAMP_DATETIME ||
timestamp_type == MYSQL_TIMESTAMP_DATE)
/*
Do not return yet, we may still want to throw a "trailing garbage"
warning.
*/
value= FALSE;
else
{
value= TRUE;
error= 1; /* force warning */
}
if (error > 0)
make_truncated_value_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
str->ptr(), str->length(),
warn_type, warn_name);
return value;
}
/**
@brief Convert date provided in a string to the int representation.
@param[in] thd thread handle
@param[in] str a string to convert
@param[in] warn_type type of the timestamp for issuing the warning
@param[in] warn_name field name for issuing the warning
@param[out] error_arg could not extract a DATE or DATETIME
@details Convert date provided in the string str to the int
representation. If the string contains wrong date or doesn't
contain it at all then a warning is issued. The warn_type and
the warn_name arguments are used as the name and the type of the
field when issuing the warning.
@return
converted value. 0 on error and on zero-dates -- check 'failure'
*/
static ulonglong get_date_from_str(THD *thd, String *str,
timestamp_type warn_type,
const char *warn_name, bool *error_arg)
{
MYSQL_TIME l_time;
*error_arg= get_mysql_time_from_str(thd, str, warn_type, warn_name, &l_time);
if (*error_arg)
return 0;
return TIME_to_ulonglong_datetime(&l_time);
}
/*
Check whether compare_datetime() can be used to compare items.
SYNOPSIS
Arg_comparator::can_compare_as_dates()
a, b [in] items to be compared
const_value [out] converted value of the string constant, if any
DESCRIPTION
Check several cases when the DATE/DATETIME comparator should be used.
The following cases are checked:
1. Both a and b is a DATE/DATETIME field/function returning string or
int result.
2. Only a or b is a DATE/DATETIME field/function returning string or
int result and the other item (b or a) is an item with string result.
If the second item is a constant one then it's checked to be
convertible to the DATE/DATETIME type. If the constant can't be
converted to a DATE/DATETIME then the compare_datetime() comparator
isn't used and the warning about wrong DATE/DATETIME value is issued.
In all other cases (date-[int|real|decimal]/[int|real|decimal]-date)
the comparison is handled by other comparators.
If the datetime comparator can be used and one the operands of the
comparison is a string constant that was successfully converted to a
DATE/DATETIME type then the result of the conversion is returned in the
const_value if it is provided. If there is no constant or
compare_datetime() isn't applicable then the *const_value remains
unchanged.
RETURN
the found type of date comparison
*/
enum Arg_comparator::enum_date_cmp_type
Arg_comparator::can_compare_as_dates(Item *a, Item *b, ulonglong *const_value)
{
enum enum_date_cmp_type cmp_type= CMP_DATE_DFLT;
Item *str_arg= 0, *date_arg= 0;
if (a->type() == Item::ROW_ITEM || b->type() == Item::ROW_ITEM)
return CMP_DATE_DFLT;
if (a->is_datetime())
{
if (b->is_datetime())
cmp_type= CMP_DATE_WITH_DATE;
else if (b->result_type() == STRING_RESULT)
{
cmp_type= CMP_DATE_WITH_STR;
date_arg= a;
str_arg= b;
}
}
else if (b->is_datetime() && a->result_type() == STRING_RESULT)
{
cmp_type= CMP_STR_WITH_DATE;
date_arg= b;
str_arg= a;
}
if (cmp_type != CMP_DATE_DFLT)
{
THD *thd= current_thd;
/*
Do not cache GET_USER_VAR() function as its const_item() may return TRUE
for the current thread but it still may change during the execution.
Don't use cache while in the context analysis mode only (i.e. for
EXPLAIN/CREATE VIEW and similar queries). Cache is useless in such
cases and can cause problems. For example evaluating subqueries can
confuse storage engines since in context analysis mode tables
aren't locked.
*/
if (!thd->lex->is_ps_or_view_context_analysis() &&
cmp_type != CMP_DATE_WITH_DATE && str_arg->const_item() &&
(str_arg->type() != Item::FUNC_ITEM ||
((Item_func*)str_arg)->functype() != Item_func::GUSERVAR_FUNC))
{
ulonglong value;
bool error;
String tmp, *str_val= 0;
timestamp_type t_type= (date_arg->field_type() == MYSQL_TYPE_DATE ?
MYSQL_TIMESTAMP_DATE : MYSQL_TIMESTAMP_DATETIME);
str_val= str_arg->val_str(&tmp);
if (str_arg->null_value)
return CMP_DATE_DFLT;
value= get_date_from_str(thd, str_val, t_type, date_arg->name, &error);
if (error)
return CMP_DATE_DFLT;
if (const_value)
*const_value= value;
}
}
return cmp_type;
}
/*
Retrieves correct TIME value from the given item.
SYNOPSIS
get_time_value()
thd thread handle
item_arg [in/out] item to retrieve TIME value from
cache_arg [in/out] pointer to place to store the cache item to
warn_item [in] unused
is_null [out] TRUE <=> the item_arg is null
DESCRIPTION
Retrieves the correct TIME value from given item for comparison by the
compare_datetime() function.
If item's result can be compared as longlong then its int value is used
and a value returned by get_time function is used otherwise.
If an item is a constant one then its value is cached and it isn't
get parsed again. An Item_cache_int object is used for for cached values.
It seamlessly substitutes the original item. The cache item is marked as
non-constant to prevent re-caching it again.
RETURN
obtained value
*/
longlong
get_time_value(THD *thd, Item ***item_arg, Item **cache_arg,
Item *warn_item, bool *is_null)
{
longlong value;
Item *item= **item_arg;
MYSQL_TIME ltime;
if (item->result_as_longlong())
{
value= item->val_int();
*is_null= item->null_value;
}
else
{
*is_null= item->get_time(&ltime);
value= !*is_null ? (longlong) TIME_to_ulonglong_datetime(&ltime) : 0;
}
/*
Do not cache GET_USER_VAR() function as its const_item() may return TRUE
for the current thread but it still may change during the execution.
*/
if (item->const_item() && cache_arg && (item->type() != Item::FUNC_ITEM ||
((Item_func*)item)->functype() != Item_func::GUSERVAR_FUNC))
{
Query_arena backup;
Query_arena *save_arena= thd->switch_to_arena_for_cached_items(&backup);
Item_cache_int *cache= new Item_cache_int();
if (save_arena)
thd->set_query_arena(save_arena);
/* Mark the cache as non-const to prevent re-caching. */
cache->set_used_tables(1);
cache->store_longlong(item, value);
*cache_arg= cache;
*item_arg= cache_arg;
}
return value;
}
int Arg_comparator::set_cmp_func(Item_result_field *owner_arg,
Item **a1, Item **a2,
Item_result type)
{
ulonglong const_value= (ulonglong)-1;
thd= current_thd;
owner= owner_arg;
set_null= set_null && owner_arg;
a= a1;
b= a2;
thd= current_thd;
if (can_compare_as_dates(*a, *b, &const_value))
{
a_type= (*a)->field_type();
b_type= (*b)->field_type();
a_cache= 0;
b_cache= 0;
if (const_value != (ulonglong)-1)
{
/*
cache_converted_constant can't be used here because it can't
correctly convert a DATETIME value from string to int representation.
*/
Query_arena backup;
Query_arena *save_arena= thd->switch_to_arena_for_cached_items(&backup);
Item_cache_int *cache= new Item_cache_int();
if (save_arena)
thd->set_query_arena(save_arena);
/* Mark the cache as non-const to prevent re-caching. */
cache->set_used_tables(1);
if (!(*a)->is_datetime())
{
cache->store_longlong((*a), const_value);
a_cache= cache;
a= (Item **)&a_cache;
}
else
{
cache->store_longlong((*b), const_value);
b_cache= cache;
b= (Item **)&b_cache;
}
}
is_nulls_eq= is_owner_equal_func();
func= &Arg_comparator::compare_datetime;
get_value_a_func= &get_datetime_value;
get_value_b_func= &get_datetime_value;
return 0;
}
else if (type == STRING_RESULT && (*a)->field_type() == MYSQL_TYPE_TIME &&
(*b)->field_type() == MYSQL_TYPE_TIME)
{
/* Compare TIME values as integers. */
a_cache= 0;
b_cache= 0;
is_nulls_eq= is_owner_equal_func();
func= &Arg_comparator::compare_datetime;
get_value_a_func= &get_time_value;
get_value_b_func= &get_time_value;
return 0;
}
else if (type == STRING_RESULT &&
(*a)->result_type() == STRING_RESULT &&
(*b)->result_type() == STRING_RESULT)
{
DTCollation coll;
coll.set((*a)->collation.collation);
if (agg_item_set_converter(coll, owner->func_name(),
b, 1, MY_COLL_CMP_CONV, 1))
return 1;
}
else if (try_year_cmp_func(type))
return 0;
a= cache_converted_constant(thd, a, &a_cache, type);
b= cache_converted_constant(thd, b, &b_cache, type);
return set_compare_func(owner_arg, type);
}
/*
Helper function to call from Arg_comparator::set_cmp_func()
*/
bool Arg_comparator::try_year_cmp_func(Item_result type)
{
if (type == ROW_RESULT)
return FALSE;
bool a_is_year= (*a)->field_type() == MYSQL_TYPE_YEAR;
bool b_is_year= (*b)->field_type() == MYSQL_TYPE_YEAR;
if (!a_is_year && !b_is_year)
return FALSE;
if (a_is_year && b_is_year)
{
get_value_a_func= &get_year_value;
get_value_b_func= &get_year_value;
}
else if (a_is_year && (*b)->is_datetime())
{
get_value_a_func= &get_year_value;
get_value_b_func= &get_datetime_value;
}
else if (b_is_year && (*a)->is_datetime())
{
get_value_b_func= &get_year_value;
get_value_a_func= &get_datetime_value;
}
else
return FALSE;
is_nulls_eq= is_owner_equal_func();
func= &Arg_comparator::compare_datetime;
return TRUE;
}
/**
Convert and cache a constant.
@param value [in] An item to cache
@param cache_item [out] Placeholder for the cache item
@param type [in] Comparison type
@details
When given item is a constant and its type differs from comparison type
then cache its value to avoid type conversion of this constant on each
evaluation. In this case the value is cached and the reference to the cache
is returned.
Original value is returned otherwise.
@return cache item or original value.
*/
Item** Arg_comparator::cache_converted_constant(THD *thd_arg, Item **value,
Item **cache_item,
Item_result type)
{
/* Don't need cache if doing context analysis only. */
if (!thd->lex->is_ps_or_view_context_analysis() &&
(*value)->const_item() && type != (*value)->result_type())
{
Item_cache *cache= Item_cache::get_cache(*value, type);
cache->setup(*value);
*cache_item= cache;
return cache_item;
}
return value;
}
void Arg_comparator::set_datetime_cmp_func(Item_result_field *owner_arg,
Item **a1, Item **b1)
{
thd= current_thd;
owner= owner_arg;
a= a1;
b= b1;
a_type= (*a)->field_type();
b_type= (*b)->field_type();
a_cache= 0;
b_cache= 0;
is_nulls_eq= FALSE;
func= &Arg_comparator::compare_datetime;
get_value_a_func= &get_datetime_value;
get_value_b_func= &get_datetime_value;
}
/*
Retrieves correct DATETIME value from given item.
SYNOPSIS
get_datetime_value()
thd thread handle
item_arg [in/out] item to retrieve DATETIME value from
cache_arg [in/out] pointer to place to store the caching item to
warn_item [in] item for issuing the conversion warning
is_null [out] TRUE <=> the item_arg is null
DESCRIPTION
Retrieves the correct DATETIME value from given item for comparison by the
compare_datetime() function.
If item's result can be compared as longlong then its int value is used
and its string value is used otherwise. Strings are always parsed and
converted to int values by the get_date_from_str() function.
This allows us to compare correctly string dates with missed insignificant
zeros. If an item is a constant one then its value is cached and it isn't
get parsed again. An Item_cache_int object is used for caching values. It
seamlessly substitutes the original item. The cache item is marked as
non-constant to prevent re-caching it again. In order to compare
correctly DATE and DATETIME items the result of the former are treated as
a DATETIME with zero time (00:00:00).
RETURN
obtained value
*/
longlong
get_datetime_value(THD *thd, Item ***item_arg, Item **cache_arg,
Item *warn_item, bool *is_null)
{
longlong value= 0;
String buf, *str= 0;
Item *item= **item_arg;
if (item->result_as_longlong())
{
value= item->val_int();
*is_null= item->null_value;
enum_field_types f_type= item->field_type();
/*
Item_date_add_interval may return MYSQL_TYPE_STRING as the result
field type. To detect that the DATE value has been returned we
compare it with 100000000L - any DATE value should be less than it.
Don't shift cached DATETIME values up for the second time.
*/
if (f_type == MYSQL_TYPE_DATE ||
(f_type != MYSQL_TYPE_DATETIME && value < 100000000L))
value*= 1000000L;
}
else
{
str= item->val_str(&buf);
*is_null= item->null_value;
}
if (*is_null)
return ~(ulonglong) 0;
/*
Convert strings to the integer DATE/DATETIME representation.
Even if both dates provided in strings we can't compare them directly as
strings as there is no warranty that they are correct and do not miss
some insignificant zeros.
*/
if (str)
{
bool error;
enum_field_types f_type= warn_item->field_type();
timestamp_type t_type= f_type ==
MYSQL_TYPE_DATE ? MYSQL_TIMESTAMP_DATE : MYSQL_TIMESTAMP_DATETIME;
value= (longlong) get_date_from_str(thd, str, t_type, warn_item->name, &error);
/*
If str did not contain a valid date according to the current
SQL_MODE, get_date_from_str() has already thrown a warning,
and we don't want to throw NULL on invalid date (see 5.2.6
"SQL modes" in the manual), so we're done here.
*/
}
/*
Do not cache GET_USER_VAR() function as its const_item() may return TRUE
for the current thread but it still may change during the execution.
*/
if (item->const_item() && cache_arg && (item->type() != Item::FUNC_ITEM ||
((Item_func*)item)->functype() != Item_func::GUSERVAR_FUNC))
{
Query_arena backup;
Query_arena *save_arena= thd->switch_to_arena_for_cached_items(&backup);
Item_cache_int *cache= new Item_cache_int(MYSQL_TYPE_DATETIME);
if (save_arena)
thd->set_query_arena(save_arena);
/* Mark the cache as non-const to prevent re-caching. */
cache->set_used_tables(1);
cache->store_longlong(item, value);
*cache_arg= cache;
*item_arg= cache_arg;
}
return value;
}
/*
Retrieves YEAR value of 19XX-00-00 00:00:00 form from given item.
SYNOPSIS
get_year_value()
thd thread handle
item_arg [in/out] item to retrieve YEAR value from
cache_arg [in/out] pointer to place to store the caching item to
warn_item [in] item for issuing the conversion warning
is_null [out] TRUE <=> the item_arg is null
DESCRIPTION
Retrieves the YEAR value of 19XX form from given item for comparison by the
compare_datetime() function.
Converts year to DATETIME of form YYYY-00-00 00:00:00 for the compatibility
with the get_datetime_value function result.
RETURN
obtained value
*/
static longlong
get_year_value(THD *thd, Item ***item_arg, Item **cache_arg,
Item *warn_item, bool *is_null)
{
longlong value= 0;
Item *item= **item_arg;
value= item->val_int();
*is_null= item->null_value;
if (*is_null)
return ~(ulonglong) 0;
/*
Coerce value to the 19XX form in order to correctly compare
YEAR(2) & YEAR(4) types.
Here we are converting all item values but YEAR(4) fields since
1) YEAR(4) already has a regular YYYY form and
2) we don't want to convert zero/bad YEAR(4) values to the
value of 2000.
*/
Item *real_item= item->real_item();
Field *field= NULL;
if (real_item->type() == Item::FIELD_ITEM)
field= ((Item_field *)real_item)->field;
else if (real_item->type() == Item::CACHE_ITEM)
field= ((Item_cache *)real_item)->field();
if (!(field && field->type() == MYSQL_TYPE_YEAR && field->field_length == 4))
{
if (value < 70)
value+= 100;
if (value <= 1900)
value+= 1900;
}
/* Convert year to DATETIME of form YYYY-00-00 00:00:00 (YYYY0000000000). */
value*= 10000000000LL;
return value;
}
/*
Compare items values as dates.
SYNOPSIS
Arg_comparator::compare_datetime()
DESCRIPTION
Compare items values as DATE/DATETIME for both EQUAL_FUNC and from other
comparison functions. The correct DATETIME values are obtained
with help of the get_datetime_value() function.
RETURN
If is_nulls_eq is TRUE:
1 if items are equal or both are null
0 otherwise
If is_nulls_eq is FALSE:
-1 a < b or at least one item is null
0 a == b
1 a > b
See the table:
is_nulls_eq | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 |
a_is_null | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |
b_is_null | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 0 |
result | 1 | 0 | 0 |0/1|-1 |-1 |-1 |-1/0/1|
*/
int Arg_comparator::compare_datetime()
{
bool a_is_null, b_is_null;
longlong a_value, b_value;
/* Get DATE/DATETIME/TIME value of the 'a' item. */
a_value= (*get_value_a_func)(thd, &a, &a_cache, *b, &a_is_null);
if (!is_nulls_eq && a_is_null)
{
if (set_null)
owner->null_value= 1;
return -1;
}
/* Get DATE/DATETIME/TIME value of the 'b' item. */
b_value= (*get_value_b_func)(thd, &b, &b_cache, *a, &b_is_null);
if (a_is_null || b_is_null)
{
if (set_null)
owner->null_value= is_nulls_eq ? 0 : 1;
return is_nulls_eq ? (a_is_null == b_is_null) : -1;
}
/* Here we have two not-NULL values. */
if (set_null)
owner->null_value= 0;
/* Compare values. */
if (is_nulls_eq)
return (a_value == b_value);
return a_value < b_value ? -1 : (a_value > b_value ? 1 : 0);
}
int Arg_comparator::compare_string()
{
String *res1,*res2;
if ((res1= (*a)->val_str(&value1)))
{
if ((res2= (*b)->val_str(&value2)))
{
if (set_null)
owner->null_value= 0;
return sortcmp(res1,res2,cmp_collation.collation);
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
/**
Compare strings byte by byte. End spaces are also compared.
@retval
<0 *a < *b
@retval
0 *b == *b
@retval
>0 *a > *b
*/
int Arg_comparator::compare_binary_string()
{
String *res1,*res2;
if ((res1= (*a)->val_str(&value1)))
{
if ((res2= (*b)->val_str(&value2)))
{
if (set_null)
owner->null_value= 0;
uint res1_length= res1->length();
uint res2_length= res2->length();
int cmp= memcmp(res1->ptr(), res2->ptr(), min(res1_length,res2_length));
return cmp ? cmp : (int) (res1_length - res2_length);
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
/**
Compare strings, but take into account that NULL == NULL.
*/
int Arg_comparator::compare_e_string()
{
String *res1,*res2;
res1= (*a)->val_str(&value1);
res2= (*b)->val_str(&value2);
if (!res1 || !res2)
return test(res1 == res2);
return test(sortcmp(res1, res2, cmp_collation.collation) == 0);
}
int Arg_comparator::compare_e_binary_string()
{
String *res1,*res2;
res1= (*a)->val_str(&value1);
res2= (*b)->val_str(&value2);
if (!res1 || !res2)
return test(res1 == res2);
return test(stringcmp(res1, res2) == 0);
}
int Arg_comparator::compare_real()
{
/*
Fix yet another manifestation of Bug#2338. 'Volatile' will instruct
gcc to flush double values out of 80-bit Intel FPU registers before
performing the comparison.
*/
volatile double val1, val2;
val1= (*a)->val_real();
if (!(*a)->null_value)
{
val2= (*b)->val_real();
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_decimal()
{
my_decimal decimal1;
my_decimal *val1= (*a)->val_decimal(&decimal1);
if (!(*a)->null_value)
{
my_decimal decimal2;
my_decimal *val2= (*b)->val_decimal(&decimal2);
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
return my_decimal_cmp(val1, val2);
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_e_real()
{
double val1= (*a)->val_real();
double val2= (*b)->val_real();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(val1 == val2);
}
int Arg_comparator::compare_e_decimal()
{
my_decimal decimal1, decimal2;
my_decimal *val1= (*a)->val_decimal(&decimal1);
my_decimal *val2= (*b)->val_decimal(&decimal2);
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(my_decimal_cmp(val1, val2) == 0);
}
int Arg_comparator::compare_real_fixed()
{
/*
Fix yet another manifestation of Bug#2338. 'Volatile' will instruct
gcc to flush double values out of 80-bit Intel FPU registers before
performing the comparison.
*/
volatile double val1, val2;
val1= (*a)->val_real();
if (!(*a)->null_value)
{
val2= (*b)->val_real();
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
if (val1 == val2 || fabs(val1 - val2) < precision)
return 0;
if (val1 < val2)
return -1;
return 1;
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_e_real_fixed()
{
double val1= (*a)->val_real();
double val2= (*b)->val_real();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(val1 == val2 || fabs(val1 - val2) < precision);
}
int Arg_comparator::compare_int_signed()
{
longlong val1= (*a)->val_int();
if (!(*a)->null_value)
{
longlong val2= (*b)->val_int();
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
/**
Compare values as BIGINT UNSIGNED.
*/
int Arg_comparator::compare_int_unsigned()
{
ulonglong val1= (*a)->val_int();
if (!(*a)->null_value)
{
ulonglong val2= (*b)->val_int();
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
/**
Compare signed (*a) with unsigned (*B)
*/
int Arg_comparator::compare_int_signed_unsigned()
{
longlong sval1= (*a)->val_int();
if (!(*a)->null_value)
{
ulonglong uval2= (ulonglong)(*b)->val_int();
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
if (sval1 < 0 || (ulonglong)sval1 < uval2)
return -1;
if ((ulonglong)sval1 == uval2)
return 0;
return 1;
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
/**
Compare unsigned (*a) with signed (*B)
*/
int Arg_comparator::compare_int_unsigned_signed()
{
ulonglong uval1= (ulonglong)(*a)->val_int();
if (!(*a)->null_value)
{
longlong sval2= (*b)->val_int();
if (!(*b)->null_value)
{
if (set_null)
owner->null_value= 0;
if (sval2 < 0)
return 1;
if (uval1 < (ulonglong)sval2)
return -1;
if (uval1 == (ulonglong)sval2)
return 0;
return 1;
}
}
if (set_null)
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_e_int()
{
longlong val1= (*a)->val_int();
longlong val2= (*b)->val_int();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(val1 == val2);
}
/**
Compare unsigned *a with signed *b or signed *a with unsigned *b.
*/
int Arg_comparator::compare_e_int_diff_signedness()
{
longlong val1= (*a)->val_int();
longlong val2= (*b)->val_int();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return (val1 >= 0) && test(val1 == val2);
}
int Arg_comparator::compare_row()
{
int res= 0;
bool was_null= 0;
(*a)->bring_value();
(*b)->bring_value();
if ((*a)->null_value || (*b)->null_value)
{
owner->null_value= 1;
return -1;
}
uint n= (*a)->cols();
for (uint i= 0; i<n; i++)
{
res= comparators[i].compare();
/* Aggregate functions don't need special null handling. */
if (owner->null_value && owner->type() == Item::FUNC_ITEM)
{
// NULL was compared
switch (((Item_func*)owner)->functype()) {
case Item_func::NE_FUNC:
break; // NE never aborts on NULL even if abort_on_null is set
case Item_func::LT_FUNC:
case Item_func::LE_FUNC:
case Item_func::GT_FUNC:
case Item_func::GE_FUNC:
return -1; // <, <=, > and >= always fail on NULL
default: // EQ_FUNC
if (((Item_bool_func2*)owner)->abort_on_null)
return -1; // We do not need correct NULL returning
}
was_null= 1;
owner->null_value= 0;
res= 0; // continue comparison (maybe we will meet explicit difference)
}
else if (res)
return res;
}
if (was_null)
{
/*
There was NULL(s) in comparison in some parts, but there was no
explicit difference in other parts, so we have to return NULL.
*/
owner->null_value= 1;
return -1;
}
return 0;
}
int Arg_comparator::compare_e_row()
{
(*a)->bring_value();
(*b)->bring_value();
uint n= (*a)->cols();
for (uint i= 0; i<n; i++)
{
if (!comparators[i].compare())
return 0;
}
return 1;
}
void Item_func_truth::fix_length_and_dec()
{
maybe_null= 0;
null_value= 0;
decimals= 0;
max_length= 1;
}
void Item_func_truth::print(String *str, enum_query_type query_type)
{
str->append('(');
args[0]->print(str, query_type);
str->append(STRING_WITH_LEN(" is "));
if (! affirmative)
str->append(STRING_WITH_LEN("not "));
if (value)
str->append(STRING_WITH_LEN("true"));
else
str->append(STRING_WITH_LEN("false"));
str->append(')');
}
bool Item_func_truth::val_bool()
{
bool val= args[0]->val_bool();
if (args[0]->null_value)
{
/*
NULL val IS {TRUE, FALSE} --> FALSE
NULL val IS NOT {TRUE, FALSE} --> TRUE
*/
return (! affirmative);
}
if (affirmative)
{
/* {TRUE, FALSE} val IS {TRUE, FALSE} value */
return (val == value);
}
/* {TRUE, FALSE} val IS NOT {TRUE, FALSE} value */
return (val != value);
}
longlong Item_func_truth::val_int()
{
return (val_bool() ? 1 : 0);
}
bool Item_in_optimizer::fix_left(THD *thd, Item **ref)
{
if ((!args[0]->fixed && args[0]->fix_fields(thd, args)) ||
(!cache && !(cache= Item_cache::get_cache(args[0]))))
return 1;
cache->setup(args[0]);
if (cache->cols() == 1)
{
if ((used_tables_cache= args[0]->used_tables()))
cache->set_used_tables(OUTER_REF_TABLE_BIT);
else
cache->set_used_tables(0);
}
else
{
uint n= cache->cols();
for (uint i= 0; i < n; i++)
{
if (args[0]->element_index(i)->used_tables())
((Item_cache *)cache->element_index(i))->set_used_tables(OUTER_REF_TABLE_BIT);
else
((Item_cache *)cache->element_index(i))->set_used_tables(0);
}
used_tables_cache= args[0]->used_tables();
}
not_null_tables_cache= args[0]->not_null_tables();
with_sum_func= args[0]->with_sum_func;
if ((const_item_cache= args[0]->const_item()))
cache->store(args[0]);
return 0;
}
bool Item_in_optimizer::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if (fix_left(thd, ref))
return TRUE;
if (args[0]->maybe_null)
maybe_null=1;
if (!args[1]->fixed && args[1]->fix_fields(thd, args+1))
return TRUE;
Item_in_subselect * sub= (Item_in_subselect *)args[1];
if (args[0]->cols() != sub->engine->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), args[0]->cols());
return TRUE;
}
if (args[1]->maybe_null)
maybe_null=1;
with_sum_func= with_sum_func || args[1]->with_sum_func;
used_tables_cache|= args[1]->used_tables();
not_null_tables_cache|= args[1]->not_null_tables();
const_item_cache&= args[1]->const_item();
fixed= 1;
return FALSE;
}
/**
Add an expression cache for this subquery if it is needed
@param thd_arg Thread handle
@details
The function checks whether an expression cache is needed for this item
and if if so wraps the item into an item of the class
Item_exp_cache_wrapper with an appropriate expression cache set up there.
@note
used from Item::transform()
@return
new wrapper item if an expression cache is needed,
this item - otherwise
*/
Item *Item_in_optimizer::expr_cache_insert_transformer(uchar *thd_arg)
{
THD *thd= (THD*) thd_arg;
DBUG_ENTER("Item_in_optimizer::expr_cache_insert_transformer");
List<Item*> &depends_on= ((Item_subselect *)args[1])->depends_on;
if (expr_cache)
DBUG_RETURN(expr_cache);
/* Add left expression to the list of the parameters of the subquery */
if (args[0]->cols() == 1)
depends_on.push_front((Item**)args);
else
{
for (uint i= 0; i < args[0]->cols(); i++)
{
depends_on.push_front(args[0]->addr(i));
}
}
if (args[1]->expr_cache_is_needed(thd) &&
(expr_cache= set_expr_cache(thd, depends_on)))
DBUG_RETURN(expr_cache);
/* no cache => return list in original state just to be safe */
for (uint i= 0; i < args[0]->cols(); i++)
depends_on.pop();
DBUG_RETURN(this);
}
/*
The implementation of optimized \<outer expression\> [NOT] IN \<subquery\>
predicates. The implementation works as follows.
For the current value of the outer expression
- If it contains only NULL values, the original (before rewrite by the
Item_in_subselect rewrite methods) inner subquery is non-correlated and
was previously executed, there is no need to re-execute it, and the
previous return value is returned.
- If it contains NULL values, check if there is a partial match for the
inner query block by evaluating it. For clarity we repeat here the
transformation previously performed on the sub-query. The expression
<tt>
( oc_1, ..., oc_n )
\<in predicate\>
( SELECT ic_1, ..., ic_n
FROM \<table\>
WHERE \<inner where\>
)
</tt>
was transformed into
<tt>
( oc_1, ..., oc_n )
\<in predicate\>
( SELECT ic_1, ..., ic_n
FROM \<table\>
WHERE \<inner where\> AND ... ( ic_k = oc_k OR ic_k IS NULL )
HAVING ... NOT ic_k IS NULL
)
</tt>
The evaluation will now proceed according to special rules set up
elsewhere. These rules include:
- The HAVING NOT \<inner column\> IS NULL conditions added by the
aforementioned rewrite methods will detect whether they evaluated (and
rejected) a NULL value and if so, will cause the subquery to evaluate
to NULL.
- The added WHERE and HAVING conditions are present only for those inner
columns that correspond to outer column that are not NULL at the moment.
- If there is an eligible index for executing the subquery, the special
access method "Full scan on NULL key" is employed which ensures that
the inner query will detect if there are NULL values resulting from the
inner query. This access method will quietly resort to table scan if it
needs to find NULL values as well.
- Under these conditions, the sub-query need only be evaluated in order to
find out whether it produced any rows.
- If it did, we know that there was a partial match since there are
NULL values in the outer row expression.
- If it did not, the result is FALSE or UNKNOWN. If at least one of the
HAVING sub-predicates rejected a NULL value corresponding to an outer
non-NULL, and hence the inner query block returns UNKNOWN upon
evaluation, there was a partial match and the result is UNKNOWN.
- If it contains no NULL values, the call is forwarded to the inner query
block.
@see Item_in_subselect::val_bool()
@see Item_is_not_null_test::val_int()
*/
longlong Item_in_optimizer::val_int()
{
bool tmp;
DBUG_ASSERT(fixed == 1);
cache->store(args[0]);
cache->cache_value();
if (cache->null_value)
{
/*
We're evaluating
"<outer_value_list> [NOT] IN (SELECT <inner_value_list>...)"
where one or more of the outer values is NULL.
*/
if (((Item_in_subselect*)args[1])->is_top_level_item())
{
/*
We're evaluating a top level item, e.g.
"<outer_value_list> IN (SELECT <inner_value_list>...)",
and in this case a NULL value in the outer_value_list means
that the result shall be NULL/FALSE (makes no difference for
top level items). The cached value is NULL, so just return
NULL.
*/
null_value= 1;
}
else
{
/*
We're evaluating an item where a NULL value in either the
outer or inner value list does not automatically mean that we
can return NULL/FALSE. An example of such a query is
"<outer_value_list> NOT IN (SELECT <inner_value_list>...)"
The result when there is at least one NULL value is: NULL if the
SELECT evaluated over the non-NULL values produces at least
one row, FALSE otherwise
*/
Item_in_subselect *item_subs=(Item_in_subselect*)args[1];
bool all_left_cols_null= true;
const uint ncols= cache->cols();
/*
Turn off the predicates that are based on column compares for
which the left part is currently NULL
*/
for (uint i= 0; i < ncols; i++)
{
if (cache->element_index(i)->null_value)
item_subs->set_cond_guard_var(i, FALSE);
else
all_left_cols_null= false;
}
if (!item_subs->is_correlated &&
all_left_cols_null && result_for_null_param != UNKNOWN)
{
/*
This is a non-correlated subquery, all values in the outer
value list are NULL, and we have already evaluated the
subquery for all NULL values: Return the same result we
did last time without evaluating the subquery.
*/
null_value= result_for_null_param;
}
else
{
/* The subquery has to be evaluated */
(void) item_subs->val_bool_result();
if (item_subs->engine->no_rows())
null_value= item_subs->null_value;
else
null_value= TRUE;
if (all_left_cols_null)
result_for_null_param= null_value;
}
/* Turn all predicates back on */
for (uint i= 0; i < ncols; i++)
item_subs->set_cond_guard_var(i, TRUE);
}
return 0;
}
tmp= args[1]->val_bool_result();
null_value= args[1]->null_value;
return tmp;
}
void Item_in_optimizer::keep_top_level_cache()
{
cache->keep_array();
save_cache= 1;
}
void Item_in_optimizer::cleanup()
{
DBUG_ENTER("Item_in_optimizer::cleanup");
Item_bool_func::cleanup();
if (!save_cache)
cache= 0;
expr_cache= 0;
DBUG_VOID_RETURN;
}
bool Item_in_optimizer::is_null()
{
val_int();
return null_value;
}
/**
Transform an Item_in_optimizer and its arguments with a callback function.
@param transformer the transformer callback function to be applied to the
nodes of the tree of the object
@param parameter to be passed to the transformer
@detail
Recursively transform the left and the right operand of this Item. The
Right operand is an Item_in_subselect or its subclass. To avoid the
creation of new Items, we use the fact the the left operand of the
Item_in_subselect is the same as the one of 'this', so instead of
transforming its operand, we just assign the left operand of the
Item_in_subselect to be equal to the left operand of 'this'.
The transformation is not applied further to the subquery operand
if the IN predicate.
@returns
@retval pointer to the transformed item
@retval NULL if an error occurred
*/
Item *Item_in_optimizer::transform(Item_transformer transformer, uchar *argument)
{
Item *new_item;
DBUG_ASSERT(!current_thd->is_stmt_prepare());
DBUG_ASSERT(arg_count == 2);
/* Transform the left IN operand. */
new_item= (*args)->transform(transformer, argument);
if (!new_item)
return 0;
/*
THD::change_item_tree() should be called only if the tree was
really transformed, i.e. when a new item has been created.
Otherwise we'll be allocating a lot of unnecessary memory for
change records at each execution.
*/
if ((*args) != new_item)
current_thd->change_item_tree(args, new_item);
/*
Transform the right IN operand which should be an Item_in_subselect or a
subclass of it. The left operand of the IN must be the same as the left
operand of this Item_in_optimizer, so in this case there is no further
transformation, we only make both operands the same.
TODO: is it the way it should be?
*/
DBUG_ASSERT((args[1])->type() == Item::SUBSELECT_ITEM &&
(((Item_subselect*)(args[1]))->substype() ==
Item_subselect::IN_SUBS ||
((Item_subselect*)(args[1]))->substype() ==
Item_subselect::ALL_SUBS ||
((Item_subselect*)(args[1]))->substype() ==
Item_subselect::ANY_SUBS));
Item_in_subselect *in_arg= (Item_in_subselect*)args[1];
in_arg->left_expr= args[0];
return (this->*transformer)(argument);
}
longlong Item_func_eq::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value == 0 ? 1 : 0;
}
/** Same as Item_func_eq, but NULL = NULL. */
void Item_func_equal::fix_length_and_dec()
{
Item_bool_func2::fix_length_and_dec();
maybe_null=null_value=0;
}
longlong Item_func_equal::val_int()
{
DBUG_ASSERT(fixed == 1);
return cmp.compare();
}
longlong Item_func_ne::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value != 0 && !null_value ? 1 : 0;
}
longlong Item_func_ge::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value >= 0 ? 1 : 0;
}
longlong Item_func_gt::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value > 0 ? 1 : 0;
}
longlong Item_func_le::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value <= 0 && !null_value ? 1 : 0;
}
longlong Item_func_lt::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value < 0 && !null_value ? 1 : 0;
}
longlong Item_func_strcmp::val_int()
{
DBUG_ASSERT(fixed == 1);
String *a=args[0]->val_str(&cmp.value1);
String *b=args[1]->val_str(&cmp.value2);
if (!a || !b)
{
null_value=1;
return 0;
}
int value= sortcmp(a,b,cmp.cmp_collation.collation);
null_value=0;
return !value ? 0 : (value < 0 ? (longlong) -1 : (longlong) 1);
}
bool Item_func_opt_neg::eq(const Item *item, bool binary_cmp) const
{
/* Assume we don't have rtti */
if (this == item)
return 1;
if (item->type() != FUNC_ITEM)
return 0;
Item_func *item_func=(Item_func*) item;
if (arg_count != item_func->arg_count ||
functype() != item_func->functype())
return 0;
if (negated != ((Item_func_opt_neg *) item_func)->negated)
return 0;
for (uint i=0; i < arg_count ; i++)
if (!args[i]->eq(item_func->arguments()[i], binary_cmp))
return 0;
return 1;
}
void Item_func_interval::fix_length_and_dec()
{
uint rows= row->cols();
use_decimal_comparison= ((row->element_index(0)->result_type() ==
DECIMAL_RESULT) ||
(row->element_index(0)->result_type() ==
INT_RESULT));
if (rows > 8)
{
bool not_null_consts= TRUE;
for (uint i= 1; not_null_consts && i < rows; i++)
{
Item *el= row->element_index(i);
not_null_consts&= el->const_item() & !el->is_null();
}
if (not_null_consts &&
(intervals=
(interval_range*) sql_alloc(sizeof(interval_range) * (rows - 1))))
{
if (use_decimal_comparison)
{
for (uint i= 1; i < rows; i++)
{
Item *el= row->element_index(i);
interval_range *range= intervals + (i-1);
if ((el->result_type() == DECIMAL_RESULT) ||
(el->result_type() == INT_RESULT))
{
range->type= DECIMAL_RESULT;
range->dec.init();
my_decimal *dec= el->val_decimal(&range->dec);
if (dec != &range->dec)
{
range->dec= *dec;
range->dec.fix_buffer_pointer();
}
}
else
{
range->type= REAL_RESULT;
range->dbl= el->val_real();
}
}
}
else
{
for (uint i= 1; i < rows; i++)
{
intervals[i-1].dbl= row->element_index(i)->val_real();
}
}
}
}
maybe_null= 0;
max_length= 2;
used_tables_cache|= row->used_tables();
not_null_tables_cache= row->not_null_tables();
with_sum_func= with_sum_func || row->with_sum_func;
const_item_cache&= row->const_item();
}
/**
Execute Item_func_interval().
@note
If we are doing a decimal comparison, we are evaluating the first
item twice.
@return
- -1 if null value,
- 0 if lower than lowest
- 1 - arg_count-1 if between args[n] and args[n+1]
- arg_count if higher than biggest argument
*/
longlong Item_func_interval::val_int()
{
DBUG_ASSERT(fixed == 1);
double value;
my_decimal dec_buf, *dec= NULL;
uint i;
if (use_decimal_comparison)
{
dec= row->element_index(0)->val_decimal(&dec_buf);
if (row->element_index(0)->null_value)
return -1;
my_decimal2double(E_DEC_FATAL_ERROR, dec, &value);
}
else
{
value= row->element_index(0)->val_real();
if (row->element_index(0)->null_value)
return -1;
}
if (intervals)
{ // Use binary search to find interval
uint start,end;
start= 0;
end= row->cols()-2;
while (start != end)
{
uint mid= (start + end + 1) / 2;
interval_range *range= intervals + mid;
my_bool cmp_result;
/*
The values in the range intervall may have different types,
Only do a decimal comparision of the first argument is a decimal
and we are comparing against a decimal
*/
if (dec && range->type == DECIMAL_RESULT)
cmp_result= my_decimal_cmp(&range->dec, dec) <= 0;
else
cmp_result= (range->dbl <= value);
if (cmp_result)
start= mid;
else
end= mid - 1;
}
interval_range *range= intervals+start;
return ((dec && range->type == DECIMAL_RESULT) ?
my_decimal_cmp(dec, &range->dec) < 0 :
value < range->dbl) ? 0 : start + 1;
}
for (i=1 ; i < row->cols() ; i++)
{
Item *el= row->element_index(i);
if (use_decimal_comparison &&
((el->result_type() == DECIMAL_RESULT) ||
(el->result_type() == INT_RESULT)))
{
my_decimal e_dec_buf, *e_dec= el->val_decimal(&e_dec_buf);
/* Skip NULL ranges. */
if (el->null_value)
continue;
if (my_decimal_cmp(e_dec, dec) > 0)
return i - 1;
}
else
{
double val= el->val_real();
/* Skip NULL ranges. */
if (el->null_value)
continue;
if (val > value)
return i - 1;
}
}
return i-1;
}
/**
Perform context analysis of a BETWEEN item tree.
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_between as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
@param thd reference to the global context of the query thread
@param ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
@note
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
@verbatim
T0(e BETWEEN e1 AND e2) = union(T1(e),T1(e1),T1(e2))
T1(e BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
T0(e NOT BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
T1(e NOT BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
@endverbatim
@retval
0 ok
@retval
1 got error
*/
bool Item_func_between::fix_fields(THD *thd, Item **ref)
{
if (Item_func_opt_neg::fix_fields(thd, ref))
return 1;
thd->lex->current_select->between_count++;
/* not_null_tables_cache == union(T1(e),T1(e1),T1(e2)) */
if (pred_level && !negated)
return 0;
/* not_null_tables_cache == union(T1(e), intersection(T1(e1),T1(e2))) */
not_null_tables_cache= (args[0]->not_null_tables() |
(args[1]->not_null_tables() &
args[2]->not_null_tables()));
return 0;
}
void Item_func_between::fix_length_and_dec()
{
max_length= 1;
int i;
bool datetime_found= FALSE;
int time_items_found= 0;
compare_as_dates= TRUE;
THD *thd= current_thd;
/*
As some compare functions are generated after sql_yacc,
we have to check for out of memory conditions here
*/
if (!args[0] || !args[1] || !args[2])
return;
if ( agg_cmp_type(&cmp_type, args, 3))
return;
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV, 1))
return;
/*
Detect the comparison of DATE/DATETIME items.
At least one of items should be a DATE/DATETIME item and other items
should return the STRING result.
*/
if (cmp_type == STRING_RESULT)
{
for (i= 0; i < 3; i++)
{
if (args[i]->is_datetime())
{
datetime_found= TRUE;
continue;
}
if (args[i]->field_type() == MYSQL_TYPE_TIME &&
args[i]->result_as_longlong())
time_items_found++;
}
}
if (!datetime_found)
compare_as_dates= FALSE;
if (compare_as_dates)
{
ge_cmp.set_datetime_cmp_func(this, args, args + 1);
le_cmp.set_datetime_cmp_func(this, args, args + 2);
}
else if (time_items_found == 3)
{
/* Compare TIME items as integers. */
cmp_type= INT_RESULT;
}
else if (args[0]->real_item()->type() == FIELD_ITEM &&
thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
thd->lex->sql_command != SQLCOM_SHOW_CREATE)
{
Item_field *field_item= (Item_field*) (args[0]->real_item());
if (field_item->field->can_be_compared_as_longlong())
{
/*
The following can't be recoded with || as convert_constant_item
changes the argument
*/
if (convert_constant_item(thd, field_item, &args[1]))
cmp_type=INT_RESULT; // Works for all types.
if (convert_constant_item(thd, field_item, &args[2]))
cmp_type=INT_RESULT; // Works for all types.
}
}
}
longlong Item_func_between::val_int()
{ // ANSI BETWEEN
DBUG_ASSERT(fixed == 1);
if (compare_as_dates)
{
int ge_res, le_res;
ge_res= ge_cmp.compare();
if ((null_value= args[0]->null_value))
return 0;
le_res= le_cmp.compare();
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((ge_res >= 0 && le_res <=0) != negated);
else if (args[1]->null_value)
{
null_value= le_res > 0; // not null if false range.
}
else
{
null_value= ge_res < 0;
}
}
else if (cmp_type == STRING_RESULT)
{
String *value,*a,*b;
value=args[0]->val_str(&value0);
if ((null_value=args[0]->null_value))
return 0;
a=args[1]->val_str(&value1);
b=args[2]->val_str(&value2);
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((sortcmp(value,a,cmp_collation.collation) >= 0 &&
sortcmp(value,b,cmp_collation.collation) <= 0) !=
negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
{
// Set to not null if false range.
null_value= sortcmp(value,b,cmp_collation.collation) <= 0;
}
else
{
// Set to not null if false range.
null_value= sortcmp(value,a,cmp_collation.collation) >= 0;
}
}
else if (cmp_type == INT_RESULT)
{
longlong value=args[0]->val_int(), a, b;
if ((null_value=args[0]->null_value))
return 0; /* purecov: inspected */
a=args[1]->val_int();
b=args[2]->val_int();
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((value >= a && value <= b) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
{
null_value= value <= b; // not null if false range.
}
else
{
null_value= value >= a;
}
}
else if (cmp_type == DECIMAL_RESULT)
{
my_decimal dec_buf, *dec= args[0]->val_decimal(&dec_buf),
a_buf, *a_dec, b_buf, *b_dec;
if ((null_value=args[0]->null_value))
return 0; /* purecov: inspected */
a_dec= args[1]->val_decimal(&a_buf);
b_dec= args[2]->val_decimal(&b_buf);
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((my_decimal_cmp(dec, a_dec) >= 0 &&
my_decimal_cmp(dec, b_dec) <= 0) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
null_value= (my_decimal_cmp(dec, b_dec) <= 0);
else
null_value= (my_decimal_cmp(dec, a_dec) >= 0);
}
else
{
double value= args[0]->val_real(),a,b;
if ((null_value=args[0]->null_value))
return 0; /* purecov: inspected */
a= args[1]->val_real();
b= args[2]->val_real();
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((value >= a && value <= b) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
{
null_value= value <= b; // not null if false range.
}
else
{
null_value= value >= a;
}
}
return (longlong) (!null_value && negated);
}
void Item_func_between::print(String *str, enum_query_type query_type)
{
str->append('(');
args[0]->print(str, query_type);
if (negated)
str->append(STRING_WITH_LEN(" not"));
str->append(STRING_WITH_LEN(" between "));
args[1]->print(str, query_type);
str->append(STRING_WITH_LEN(" and "));
args[2]->print(str, query_type);
str->append(')');
}
void
Item_func_ifnull::fix_length_and_dec()
{
agg_result_type(&hybrid_type, args, 2);
maybe_null=args[1]->maybe_null;
decimals= max(args[0]->decimals, args[1]->decimals);
unsigned_flag= args[0]->unsigned_flag && args[1]->unsigned_flag;
if (hybrid_type == DECIMAL_RESULT || hybrid_type == INT_RESULT)
{
int len0= args[0]->max_length - args[0]->decimals
- (args[0]->unsigned_flag ? 0 : 1);
int len1= args[1]->max_length - args[1]->decimals
- (args[1]->unsigned_flag ? 0 : 1);
max_length= max(len0, len1) + decimals + (unsigned_flag ? 0 : 1);
}
else
max_length= max(args[0]->max_length, args[1]->max_length);
switch (hybrid_type) {
case STRING_RESULT:
agg_arg_charsets(collation, args, arg_count, MY_COLL_CMP_CONV, 1);
break;
case DECIMAL_RESULT:
case REAL_RESULT:
break;
case INT_RESULT:
decimals= 0;
break;
case ROW_RESULT:
default:
DBUG_ASSERT(0);
}
cached_field_type= agg_field_type(args, 2);
}
uint Item_func_ifnull::decimal_precision() const
{
int arg0_int_part= args[0]->decimal_int_part();
int arg1_int_part= args[1]->decimal_int_part();
int max_int_part= max(arg0_int_part, arg1_int_part);
int precision= max_int_part + decimals;
return min(precision, DECIMAL_MAX_PRECISION);
}
enum_field_types Item_func_ifnull::field_type() const
{
return cached_field_type;
}
Field *Item_func_ifnull::tmp_table_field(TABLE *table)
{
return tmp_table_field_from_field_type(table, 0);
}
double
Item_func_ifnull::real_op()
{
DBUG_ASSERT(fixed == 1);
double value= args[0]->val_real();
if (!args[0]->null_value)
{
null_value=0;
return value;
}
value= args[1]->val_real();
if ((null_value=args[1]->null_value))
return 0.0;
return value;
}
longlong
Item_func_ifnull::int_op()
{
DBUG_ASSERT(fixed == 1);
longlong value=args[0]->val_int();
if (!args[0]->null_value)
{
null_value=0;
return value;
}
value=args[1]->val_int();
if ((null_value=args[1]->null_value))
return 0;
return value;
}
my_decimal *Item_func_ifnull::decimal_op(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
my_decimal *value= args[0]->val_decimal(decimal_value);
if (!args[0]->null_value)
{
null_value= 0;
return value;
}
value= args[1]->val_decimal(decimal_value);
if ((null_value= args[1]->null_value))
return 0;
return value;
}
String *
Item_func_ifnull::str_op(String *str)
{
DBUG_ASSERT(fixed == 1);
String *res =args[0]->val_str(str);
if (!args[0]->null_value)
{
null_value=0;
res->set_charset(collation.collation);
return res;
}
res=args[1]->val_str(str);
if ((null_value=args[1]->null_value))
return 0;
res->set_charset(collation.collation);
return res;
}
/**
Perform context analysis of an IF item tree.
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_if as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
@param thd reference to the global context of the query thread
@param ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
@note
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
@verbatim
T0(IF(e,e1,e2) = T1(IF(e,e1,e2))
T1(IF(e,e1,e2)) = intersection(T1(e1),T1(e2))
@endverbatim
@retval
0 ok
@retval
1 got error
*/
bool
Item_func_if::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
args[0]->top_level_item();
if (Item_func::fix_fields(thd, ref))
return 1;
not_null_tables_cache= (args[1]->not_null_tables() &
args[2]->not_null_tables());
return 0;
}
void
Item_func_if::fix_length_and_dec()
{
maybe_null=args[1]->maybe_null || args[2]->maybe_null;
decimals= max(args[1]->decimals, args[2]->decimals);
unsigned_flag=args[1]->unsigned_flag && args[2]->unsigned_flag;
enum Item_result arg1_type=args[1]->result_type();
enum Item_result arg2_type=args[2]->result_type();
bool null1=args[1]->const_item() && args[1]->null_value;
bool null2=args[2]->const_item() && args[2]->null_value;
if (null1)
{
cached_result_type= arg2_type;
collation.set(args[2]->collation.collation);
cached_field_type= args[2]->field_type();
}
else if (null2)
{
cached_result_type= arg1_type;
collation.set(args[1]->collation.collation);
cached_field_type= args[1]->field_type();
}
else
{
agg_result_type(&cached_result_type, args+1, 2);
if (cached_result_type == STRING_RESULT)
{
if (agg_arg_charsets(collation, args+1, 2, MY_COLL_ALLOW_CONV, 1))
return;
}
else
{
collation.set(&my_charset_bin); // Number
}
cached_field_type= agg_field_type(args + 1, 2);
}
if ((cached_result_type == DECIMAL_RESULT )
|| (cached_result_type == INT_RESULT))
{
int len1= args[1]->max_length - args[1]->decimals
- (args[1]->unsigned_flag ? 0 : 1);
int len2= args[2]->max_length - args[2]->decimals
- (args[2]->unsigned_flag ? 0 : 1);
max_length=max(len1, len2) + decimals + (unsigned_flag ? 0 : 1);
}
else
max_length= max(args[1]->max_length, args[2]->max_length);
}
uint Item_func_if::decimal_precision() const
{
int arg1_prec= args[1]->decimal_int_part();
int arg2_prec= args[2]->decimal_int_part();
int precision=max(arg1_prec,arg2_prec) + decimals;
return min(precision, DECIMAL_MAX_PRECISION);
}
double
Item_func_if::val_real()
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
double value= arg->val_real();
null_value=arg->null_value;
return value;
}
longlong
Item_func_if::val_int()
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
longlong value=arg->val_int();
null_value=arg->null_value;
return value;
}
String *
Item_func_if::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
String *res=arg->val_str(str);
if (res)
res->set_charset(collation.collation);
null_value=arg->null_value;
return res;
}
my_decimal *
Item_func_if::val_decimal(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
my_decimal *value= arg->val_decimal(decimal_value);
null_value= arg->null_value;
return value;
}
void
Item_func_nullif::fix_length_and_dec()
{
Item_bool_func2::fix_length_and_dec();
maybe_null=1;
if (args[0]) // Only false if EOM
{
max_length=args[0]->max_length;
decimals=args[0]->decimals;
unsigned_flag= args[0]->unsigned_flag;
cached_result_type= args[0]->result_type();
if (cached_result_type == STRING_RESULT &&
agg_arg_charsets(collation, args, arg_count, MY_COLL_CMP_CONV, 1))
return;
}
}
/**
@note
Note that we have to evaluate the first argument twice as the compare
may have been done with a different type than return value
@return
NULL if arguments are equal
@return
the first argument if not equal
*/
double
Item_func_nullif::val_real()
{
DBUG_ASSERT(fixed == 1);
double value;
if (!cmp.compare())
{
null_value=1;
return 0.0;
}
value= args[0]->val_real();
null_value=args[0]->null_value;
return value;
}
longlong
Item_func_nullif::val_int()
{
DBUG_ASSERT(fixed == 1);
longlong value;
if (!cmp.compare())
{
null_value=1;
return 0;
}
value=args[0]->val_int();
null_value=args[0]->null_value;
return value;
}
String *
Item_func_nullif::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
String *res;
if (!cmp.compare())
{
null_value=1;
return 0;
}
res=args[0]->val_str(str);
null_value=args[0]->null_value;
return res;
}
my_decimal *
Item_func_nullif::val_decimal(my_decimal * decimal_value)
{
DBUG_ASSERT(fixed == 1);
my_decimal *res;
if (!cmp.compare())
{
null_value=1;
return 0;
}
res= args[0]->val_decimal(decimal_value);
null_value= args[0]->null_value;
return res;
}
bool
Item_func_nullif::is_null()
{
return (null_value= (!cmp.compare() ? 1 : args[0]->null_value));
}
/**
Find and return matching items for CASE or ELSE item if all compares
are failed or NULL if ELSE item isn't defined.
IMPLEMENTATION
In order to do correct comparisons of the CASE expression (the expression
between CASE and the first WHEN) with each WHEN expression several
comparators are used. One for each result type. CASE expression can be
evaluated up to # of different result types are used. To check whether
the CASE expression already was evaluated for a particular result type
a bit mapped variable value_added_map is used. Result types are mapped
to it according to their int values i.e. STRING_RESULT is mapped to bit
0, REAL_RESULT to bit 1, so on.
@retval
NULL Nothing found and there is no ELSE expression defined
@retval
item Found item or ELSE item if defined and all comparisons are
failed
*/
Item *Item_func_case::find_item(String *str)
{
uint value_added_map= 0;
if (first_expr_num == -1)
{
for (uint i=0 ; i < ncases ; i+=2)
{
// No expression between CASE and the first WHEN
if (args[i]->val_bool())
return args[i+1];
continue;
}
}
else
{
/* Compare every WHEN argument with it and return the first match */
for (uint i=0 ; i < ncases ; i+=2)
{
if (args[i]->real_item()->type() == NULL_ITEM)
continue;
cmp_type= item_cmp_type(left_result_type, args[i]->result_type());
DBUG_ASSERT(cmp_type != ROW_RESULT);
DBUG_ASSERT(cmp_items[(uint)cmp_type]);
if (!(value_added_map & (1<<(uint)cmp_type)))
{
cmp_items[(uint)cmp_type]->store_value(args[first_expr_num]);
if ((null_value=args[first_expr_num]->null_value))
return else_expr_num != -1 ? args[else_expr_num] : 0;
value_added_map|= 1<<(uint)cmp_type;
}
if (!cmp_items[(uint)cmp_type]->cmp(args[i]) && !args[i]->null_value)
return args[i + 1];
}
}
// No, WHEN clauses all missed, return ELSE expression
return else_expr_num != -1 ? args[else_expr_num] : 0;
}
String *Item_func_case::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
String *res;
Item *item=find_item(str);
if (!item)
{
null_value=1;
return 0;
}
null_value= 0;
if (!(res=item->val_str(str)))
null_value= 1;
return res;
}
longlong Item_func_case::val_int()
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff,sizeof(buff),default_charset());
Item *item=find_item(&dummy_str);
longlong res;
if (!item)
{
null_value=1;
return 0;
}
res=item->val_int();
null_value=item->null_value;
return res;
}
double Item_func_case::val_real()
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff,sizeof(buff),default_charset());
Item *item=find_item(&dummy_str);
double res;
if (!item)
{
null_value=1;
return 0;
}
res= item->val_real();
null_value=item->null_value;
return res;
}
my_decimal *Item_func_case::val_decimal(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff, sizeof(buff), default_charset());
Item *item= find_item(&dummy_str);
my_decimal *res;
if (!item)
{
null_value=1;
return 0;
}
res= item->val_decimal(decimal_value);
null_value= item->null_value;
return res;
}
bool Item_func_case::fix_fields(THD *thd, Item **ref)
{
/*
buff should match stack usage from
Item_func_case::val_int() -> Item_func_case::find_item()
*/
#ifndef EMBEDDED_LIBRARY
uchar buff[MAX_FIELD_WIDTH*2+sizeof(String)*2+sizeof(String*)*2+sizeof(double)*2+sizeof(longlong)*2];
#endif
bool res= Item_func::fix_fields(thd, ref);
/*
Call check_stack_overrun after fix_fields to be sure that stack variable
is not optimized away
*/
if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
return TRUE; // Fatal error flag is set!
return res;
}
void Item_func_case::agg_str_lengths(Item* arg)
{
set_if_bigger(max_length, arg->max_length);
set_if_bigger(decimals, arg->decimals);
unsigned_flag= unsigned_flag && arg->unsigned_flag;
}
void Item_func_case::agg_num_lengths(Item *arg)
{
uint len= my_decimal_length_to_precision(arg->max_length, arg->decimals,
arg->unsigned_flag) - arg->decimals;
set_if_bigger(max_length, len);
set_if_bigger(decimals, arg->decimals);
unsigned_flag= unsigned_flag && arg->unsigned_flag;
}
void Item_func_case::fix_length_and_dec()
{
Item **agg;
uint nagg;
uint found_types= 0;
if (!(agg= (Item**) sql_alloc(sizeof(Item*)*(ncases+1))))
return;
/*
Aggregate all THEN and ELSE expression types
and collations when string result
*/
for (nagg= 0 ; nagg < ncases/2 ; nagg++)
agg[nagg]= args[nagg*2+1];
if (else_expr_num != -1)
agg[nagg++]= args[else_expr_num];
agg_result_type(&cached_result_type, agg, nagg);
if ((cached_result_type == STRING_RESULT) &&
agg_arg_charsets(collation, agg, nagg, MY_COLL_ALLOW_CONV, 1))
return;
cached_field_type= agg_field_type(agg, nagg);
/*
Aggregate first expression and all THEN expression types
and collations when string comparison
*/
if (first_expr_num != -1)
{
uint i;
agg[0]= args[first_expr_num];
left_result_type= agg[0]->result_type();
for (nagg= 0; nagg < ncases/2 ; nagg++)
agg[nagg+1]= args[nagg*2];
nagg++;
if (!(found_types= collect_cmp_types(agg, nagg)))
return;
if (with_sum_func || current_thd->lex->current_select->group_list.elements)
{
/*
See TODO commentary in the setup_copy_fields function:
item in a group may be wrapped with an Item_copy_string item.
That item has a STRING_RESULT result type, so we need
to take this type into account.
*/
found_types |= (1 << item_cmp_type(left_result_type, STRING_RESULT));
}
for (i= 0; i <= (uint)DECIMAL_RESULT; i++)
{
if (found_types & (1 << i) && !cmp_items[i])
{
DBUG_ASSERT((Item_result)i != ROW_RESULT);
if ((Item_result)i == STRING_RESULT &&
agg_arg_charsets(cmp_collation, agg, nagg, MY_COLL_CMP_CONV, 1))
return;
if (!(cmp_items[i]=
cmp_item::get_comparator((Item_result)i,
cmp_collation.collation)))
return;
}
}
}
if (else_expr_num == -1 || args[else_expr_num]->maybe_null)
maybe_null=1;
max_length=0;
decimals=0;
unsigned_flag= TRUE;
if (cached_result_type == STRING_RESULT)
{
for (uint i= 0; i < ncases; i+= 2)
agg_str_lengths(args[i + 1]);
if (else_expr_num != -1)
agg_str_lengths(args[else_expr_num]);
}
else
{
for (uint i= 0; i < ncases; i+= 2)
agg_num_lengths(args[i + 1]);
if (else_expr_num != -1)
agg_num_lengths(args[else_expr_num]);
max_length= my_decimal_precision_to_length(max_length + decimals, decimals,
unsigned_flag);
}
}
uint Item_func_case::decimal_precision() const
{
int max_int_part=0;
for (uint i=0 ; i < ncases ; i+=2)
set_if_bigger(max_int_part, args[i+1]->decimal_int_part());
if (else_expr_num != -1)
set_if_bigger(max_int_part, args[else_expr_num]->decimal_int_part());
return min(max_int_part + decimals, DECIMAL_MAX_PRECISION);
}
/**
@todo
Fix this so that it prints the whole CASE expression
*/
void Item_func_case::print(String *str, enum_query_type query_type)
{
str->append(STRING_WITH_LEN("(case "));
if (first_expr_num != -1)
{
args[first_expr_num]->print(str, query_type);
str->append(' ');
}
for (uint i=0 ; i < ncases ; i+=2)
{
str->append(STRING_WITH_LEN("when "));
args[i]->print(str, query_type);
str->append(STRING_WITH_LEN(" then "));
args[i+1]->print(str, query_type);
str->append(' ');
}
if (else_expr_num != -1)
{
str->append(STRING_WITH_LEN("else "));
args[else_expr_num]->print(str, query_type);
str->append(' ');
}
str->append(STRING_WITH_LEN("end)"));
}
void Item_func_case::cleanup()
{
uint i;
DBUG_ENTER("Item_func_case::cleanup");
Item_func::cleanup();
for (i= 0; i <= (uint)DECIMAL_RESULT; i++)
{
delete cmp_items[i];
cmp_items[i]= 0;
}
DBUG_VOID_RETURN;
}
/**
Coalesce - return first not NULL argument.
*/
String *Item_func_coalesce::str_op(String *str)
{
DBUG_ASSERT(fixed == 1);
null_value=0;
for (uint i=0 ; i < arg_count ; i++)
{
String *res;
if ((res=args[i]->val_str(str)))
return res;
}
null_value=1;
return 0;
}
longlong Item_func_coalesce::int_op()
{
DBUG_ASSERT(fixed == 1);
null_value=0;
for (uint i=0 ; i < arg_count ; i++)
{
longlong res=args[i]->val_int();
if (!args[i]->null_value)
return res;
}
null_value=1;
return 0;
}
double Item_func_coalesce::real_op()
{
DBUG_ASSERT(fixed == 1);
null_value=0;
for (uint i=0 ; i < arg_count ; i++)
{
double res= args[i]->val_real();
if (!args[i]->null_value)
return res;
}
null_value=1;
return 0;
}
my_decimal *Item_func_coalesce::decimal_op(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
null_value= 0;
for (uint i= 0; i < arg_count; i++)
{
my_decimal *res= args[i]->val_decimal(decimal_value);
if (!args[i]->null_value)
return res;
}
null_value=1;
return 0;
}
void Item_func_coalesce::fix_length_and_dec()
{
cached_field_type= agg_field_type(args, arg_count);
agg_result_type(&hybrid_type, args, arg_count);
switch (hybrid_type) {
case STRING_RESULT:
count_only_length();
decimals= NOT_FIXED_DEC;
agg_arg_charsets(collation, args, arg_count, MY_COLL_ALLOW_CONV, 1);
break;
case DECIMAL_RESULT:
count_decimal_length();
break;
case REAL_RESULT:
count_real_length();
break;
case INT_RESULT:
count_only_length();
decimals= 0;
break;
case ROW_RESULT:
default:
DBUG_ASSERT(0);
}
}
/****************************************************************************
Classes and function for the IN operator
****************************************************************************/
/*
Determine which of the signed longlong arguments is bigger
SYNOPSIS
cmp_longs()
a_val left argument
b_val right argument
DESCRIPTION
This function will compare two signed longlong arguments
and will return -1, 0, or 1 if left argument is smaller than,
equal to or greater than the right argument.
RETURN VALUE
-1 left argument is smaller than the right argument.
0 left argument is equal to the right argument.
1 left argument is greater than the right argument.
*/
static inline int cmp_longs (longlong a_val, longlong b_val)
{
return a_val < b_val ? -1 : a_val == b_val ? 0 : 1;
}
/*
Determine which of the unsigned longlong arguments is bigger
SYNOPSIS
cmp_ulongs()
a_val left argument
b_val right argument
DESCRIPTION
This function will compare two unsigned longlong arguments
and will return -1, 0, or 1 if left argument is smaller than,
equal to or greater than the right argument.
RETURN VALUE
-1 left argument is smaller than the right argument.
0 left argument is equal to the right argument.
1 left argument is greater than the right argument.
*/
static inline int cmp_ulongs (ulonglong a_val, ulonglong b_val)
{
return a_val < b_val ? -1 : a_val == b_val ? 0 : 1;
}
/*
Compare two integers in IN value list format (packed_longlong)
SYNOPSIS
cmp_longlong()
cmp_arg an argument passed to the calling function (my_qsort2)
a left argument
b right argument
DESCRIPTION
This function will compare two integer arguments in the IN value list
format and will return -1, 0, or 1 if left argument is smaller than,
equal to or greater than the right argument.
It's used in sorting the IN values list and finding an element in it.
Depending on the signedness of the arguments cmp_longlong() will
compare them as either signed (using cmp_longs()) or unsigned (using
cmp_ulongs()).
RETURN VALUE
-1 left argument is smaller than the right argument.
0 left argument is equal to the right argument.
1 left argument is greater than the right argument.
*/
int cmp_longlong(void *cmp_arg,
in_longlong::packed_longlong *a,
in_longlong::packed_longlong *b)
{
if (a->unsigned_flag != b->unsigned_flag)
{
/*
One of the args is unsigned and is too big to fit into the
positive signed range. Report no match.
*/
if ((a->unsigned_flag && ((ulonglong) a->val) > (ulonglong) LONGLONG_MAX)
||
(b->unsigned_flag && ((ulonglong) b->val) > (ulonglong) LONGLONG_MAX))
return a->unsigned_flag ? 1 : -1;
/*
Although the signedness differs both args can fit into the signed
positive range. Make them signed and compare as usual.
*/
return cmp_longs(a->val, b->val);
}
if (a->unsigned_flag)
return cmp_ulongs((ulonglong) a->val, (ulonglong) b->val);
return cmp_longs(a->val, b->val);
}
static int cmp_double(void *cmp_arg, double *a,double *b)
{
return *a < *b ? -1 : *a == *b ? 0 : 1;
}
static int cmp_row(void *cmp_arg, cmp_item_row *a, cmp_item_row *b)
{
return a->compare(b);
}
static int cmp_decimal(void *cmp_arg, my_decimal *a, my_decimal *b)
{
/*
We need call of fixing buffer pointer, because fast sort just copy
decimal buffers in memory and pointers left pointing on old buffer place
*/
a->fix_buffer_pointer();
b->fix_buffer_pointer();
return my_decimal_cmp(a, b);
}
int in_vector::find(Item *item)
{
uchar *result=get_value(item);
if (!result || !used_count)
return 0; // Null value
uint start,end;
start=0; end=used_count-1;
while (start != end)
{
uint mid=(start+end+1)/2;
int res;
if ((res=(*compare)(collation, base+mid*size, result)) == 0)
return 1;
if (res < 0)
start=mid;
else
end=mid-1;
}
return (int) ((*compare)(collation, base+start*size, result) == 0);
}
in_string::in_string(uint elements,qsort2_cmp cmp_func, CHARSET_INFO *cs)
:in_vector(elements, sizeof(String), cmp_func, cs),
tmp(buff, sizeof(buff), &my_charset_bin)
{}
in_string::~in_string()
{
if (base)
{
// base was allocated with help of sql_alloc => following is OK
for (uint i=0 ; i < count ; i++)
((String*) base)[i].free();
}
}
void in_string::set(uint pos,Item *item)
{
String *str=((String*) base)+pos;
String *res=item->val_str(str);
if (res && res != str)
{
if (res->uses_buffer_owned_by(str))
res->copy();
if (item->type() == Item::FUNC_ITEM)
str->copy(*res);
else
*str= *res;
}
if (!str->charset())
{
CHARSET_INFO *cs;
if (!(cs= item->collation.collation))
cs= &my_charset_bin; // Should never happen for STR items
str->set_charset(cs);
}
}
uchar *in_string::get_value(Item *item)
{
return (uchar*) item->val_str(&tmp);
}
in_row::in_row(uint elements, Item * item)
{
base= (char*) new cmp_item_row[count= elements];
size= sizeof(cmp_item_row);
compare= (qsort2_cmp) cmp_row;
/*
We need to reset these as otherwise we will call sort() with
uninitialized (even if not used) elements
*/
used_count= elements;
collation= 0;
}
in_row::~in_row()
{
if (base)
delete [] (cmp_item_row*) base;
}
uchar *in_row::get_value(Item *item)
{
tmp.store_value(item);
if (item->is_null())
return 0;
return (uchar *)&tmp;
}
void in_row::set(uint pos, Item *item)
{
DBUG_ENTER("in_row::set");
DBUG_PRINT("enter", ("pos: %u item: 0x%lx", pos, (ulong) item));
((cmp_item_row*) base)[pos].store_value_by_template(&tmp, item);
DBUG_VOID_RETURN;
}
in_longlong::in_longlong(uint elements)
:in_vector(elements,sizeof(packed_longlong),(qsort2_cmp) cmp_longlong, 0)
{}
void in_longlong::set(uint pos,Item *item)
{
struct packed_longlong *buff= &((packed_longlong*) base)[pos];
buff->val= item->val_int();
buff->unsigned_flag= item->unsigned_flag;
}
uchar *in_longlong::get_value(Item *item)
{
tmp.val= item->val_int();
if (item->null_value)
return 0;
tmp.unsigned_flag= item->unsigned_flag;
return (uchar*) &tmp;
}
void in_datetime::set(uint pos,Item *item)
{
Item **tmp_item= &item;
bool is_null;
struct packed_longlong *buff= &((packed_longlong*) base)[pos];
buff->val= get_datetime_value(thd, &tmp_item, 0, warn_item, &is_null);
buff->unsigned_flag= 1L;
}
uchar *in_datetime::get_value(Item *item)
{
bool is_null;
Item **tmp_item= lval_cache ? &lval_cache : &item;
tmp.val= get_datetime_value(thd, &tmp_item, &lval_cache, warn_item, &is_null);
if (item->null_value)
return 0;
tmp.unsigned_flag= 1L;
return (uchar*) &tmp;
}
in_double::in_double(uint elements)
:in_vector(elements,sizeof(double),(qsort2_cmp) cmp_double, 0)
{}
void in_double::set(uint pos,Item *item)
{
((double*) base)[pos]= item->val_real();
}
uchar *in_double::get_value(Item *item)
{
tmp= item->val_real();
if (item->null_value)
return 0; /* purecov: inspected */
return (uchar*) &tmp;
}
in_decimal::in_decimal(uint elements)
:in_vector(elements, sizeof(my_decimal),(qsort2_cmp) cmp_decimal, 0)
{}
void in_decimal::set(uint pos, Item *item)
{
/* as far as 'item' is constant, we can store reference on my_decimal */
my_decimal *dec= ((my_decimal *)base) + pos;
dec->len= DECIMAL_BUFF_LENGTH;
dec->fix_buffer_pointer();
my_decimal *res= item->val_decimal(dec);
/* if item->val_decimal() is evaluated to NULL then res == 0 */
if (!item->null_value && res != dec)
my_decimal2decimal(res, dec);
}
uchar *in_decimal::get_value(Item *item)
{
my_decimal *result= item->val_decimal(&val);
if (item->null_value)
return 0;
return (uchar *)result;
}
cmp_item* cmp_item::get_comparator(Item_result type,
CHARSET_INFO *cs)
{
switch (type) {
case STRING_RESULT:
return new cmp_item_sort_string(cs);
case INT_RESULT:
return new cmp_item_int;
case REAL_RESULT:
return new cmp_item_real;
case ROW_RESULT:
return new cmp_item_row;
case DECIMAL_RESULT:
return new cmp_item_decimal;
default:
DBUG_ASSERT(0);
break;
}
return 0; // to satisfy compiler :)
}
cmp_item* cmp_item_sort_string::make_same()
{
return new cmp_item_sort_string_in_static(cmp_charset);
}
cmp_item* cmp_item_int::make_same()
{
return new cmp_item_int();
}
cmp_item* cmp_item_real::make_same()
{
return new cmp_item_real();
}
cmp_item* cmp_item_row::make_same()
{
return new cmp_item_row();
}
cmp_item_row::~cmp_item_row()
{
DBUG_ENTER("~cmp_item_row");
DBUG_PRINT("enter",("this: 0x%lx", (long) this));
if (comparators)
{
for (uint i= 0; i < n; i++)
{
if (comparators[i])
delete comparators[i];
}
}
DBUG_VOID_RETURN;
}
void cmp_item_row::alloc_comparators()
{
if (!comparators)
comparators= (cmp_item **) current_thd->calloc(sizeof(cmp_item *)*n);
}
void cmp_item_row::store_value(Item *item)
{
DBUG_ENTER("cmp_item_row::store_value");
n= item->cols();
alloc_comparators();
if (comparators)
{
item->bring_value();
item->null_value= 0;
for (uint i=0; i < n; i++)
{
if (!comparators[i])
if (!(comparators[i]=
cmp_item::get_comparator(item->element_index(i)->result_type(),
item->element_index(i)->collation.collation)))
break; // new failed
comparators[i]->store_value(item->element_index(i));
item->null_value|= item->element_index(i)->null_value;
}
}
DBUG_VOID_RETURN;
}
void cmp_item_row::store_value_by_template(cmp_item *t, Item *item)
{
cmp_item_row *tmpl= (cmp_item_row*) t;
if (tmpl->n != item->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), tmpl->n);
return;
}
n= tmpl->n;
if ((comparators= (cmp_item **) sql_alloc(sizeof(cmp_item *)*n)))
{
item->bring_value();
item->null_value= 0;
for (uint i=0; i < n; i++)
{
if (!(comparators[i]= tmpl->comparators[i]->make_same()))
break; // new failed
comparators[i]->store_value_by_template(tmpl->comparators[i],
item->element_index(i));
item->null_value|= item->element_index(i)->null_value;
}
}
}
int cmp_item_row::cmp(Item *arg)
{
arg->null_value= 0;
if (arg->cols() != n)
{
my_error(ER_OPERAND_COLUMNS, MYF(0), n);
return 1;
}
bool was_null= 0;
arg->bring_value();
for (uint i=0; i < n; i++)
{
if (comparators[i]->cmp(arg->element_index(i)))
{
if (!arg->element_index(i)->null_value)
return 1;
was_null= 1;
}
}
return (arg->null_value= was_null);
}
int cmp_item_row::compare(cmp_item *c)
{
cmp_item_row *l_cmp= (cmp_item_row *) c;
for (uint i=0; i < n; i++)
{
int res;
if ((res= comparators[i]->compare(l_cmp->comparators[i])))
return res;
}
return 0;
}
void cmp_item_decimal::store_value(Item *item)
{
my_decimal *val= item->val_decimal(&value);
/* val may be zero if item is nnull */
if (val && val != &value)
my_decimal2decimal(val, &value);
}
int cmp_item_decimal::cmp(Item *arg)
{
my_decimal tmp_buf, *tmp= arg->val_decimal(&tmp_buf);
if (arg->null_value)
return 1;
return my_decimal_cmp(&value, tmp);
}
int cmp_item_decimal::compare(cmp_item *arg)
{
cmp_item_decimal *l_cmp= (cmp_item_decimal*) arg;
return my_decimal_cmp(&value, &l_cmp->value);
}
cmp_item* cmp_item_decimal::make_same()
{
return new cmp_item_decimal();
}
void cmp_item_datetime::store_value(Item *item)
{
bool is_null;
Item **tmp_item= lval_cache ? &lval_cache : &item;
value= get_datetime_value(thd, &tmp_item, &lval_cache, warn_item, &is_null);
}
int cmp_item_datetime::cmp(Item *arg)
{
bool is_null;
Item **tmp_item= &arg;
return value !=
get_datetime_value(thd, &tmp_item, 0, warn_item, &is_null);
}
int cmp_item_datetime::compare(cmp_item *ci)
{
cmp_item_datetime *l_cmp= (cmp_item_datetime *)ci;
return (value < l_cmp->value) ? -1 : ((value == l_cmp->value) ? 0 : 1);
}
cmp_item *cmp_item_datetime::make_same()
{
return new cmp_item_datetime(warn_item);
}
bool Item_func_in::nulls_in_row()
{
Item **arg,**arg_end;
for (arg= args+1, arg_end= args+arg_count; arg != arg_end ; arg++)
{
if ((*arg)->null_inside())
return 1;
}
return 0;
}
/**
Perform context analysis of an IN item tree.
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_in as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
@param thd reference to the global context of the query thread
@param ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
@note
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
@verbatim
T0(e IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
T1(e IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
T0(e NOT IN(e1,...,en)) = union(T1(e),union(T1(ei)))
T1(e NOT IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
@endverbatim
@retval
0 ok
@retval
1 got error
*/
bool
Item_func_in::fix_fields(THD *thd, Item **ref)
{
Item **arg, **arg_end;
if (Item_func_opt_neg::fix_fields(thd, ref))
return 1;
/* not_null_tables_cache == union(T1(e),union(T1(ei))) */
if (pred_level && negated)
return 0;
/* not_null_tables_cache = union(T1(e),intersection(T1(ei))) */
not_null_tables_cache= ~(table_map) 0;
for (arg= args + 1, arg_end= args + arg_count; arg != arg_end; arg++)
not_null_tables_cache&= (*arg)->not_null_tables();
not_null_tables_cache|= (*args)->not_null_tables();
return 0;
}
static int srtcmp_in(CHARSET_INFO *cs, const String *x,const String *y)
{
return cs->coll->strnncollsp(cs,
(uchar *) x->ptr(),x->length(),
(uchar *) y->ptr(),y->length(), 0);
}
void Item_func_in::fix_length_and_dec()
{
Item **arg, **arg_end;
bool const_itm= 1;
THD *thd= current_thd;
bool datetime_found= FALSE;
/* TRUE <=> arguments values will be compared as DATETIMEs. */
bool compare_as_datetime= FALSE;
Item *date_arg= 0;
uint found_types= 0;
uint type_cnt= 0, i;
Item_result cmp_type= STRING_RESULT;
left_result_type= args[0]->result_type();
if (!(found_types= collect_cmp_types(args, arg_count, true)))
return;
for (arg= args + 1, arg_end= args + arg_count; arg != arg_end ; arg++)
{
if (!arg[0]->const_item())
{
const_itm= 0;
break;
}
}
for (i= 0; i <= (uint)DECIMAL_RESULT; i++)
{
if (found_types & 1 << i)
{
(type_cnt)++;
cmp_type= (Item_result) i;
}
}
if (type_cnt == 1)
{
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, arg_count, MY_COLL_CMP_CONV, 1))
return;
arg_types_compatible= TRUE;
}
if (type_cnt == 1)
{
/*
When comparing rows create the row comparator object beforehand to ease
the DATETIME comparison detection procedure.
*/
if (cmp_type == ROW_RESULT)
{
cmp_item_row *cmp= 0;
if (const_itm && !nulls_in_row())
{
array= new in_row(arg_count-1, 0);
cmp= &((in_row*)array)->tmp;
}
else
{
if (!(cmp= new cmp_item_row))
return;
cmp_items[ROW_RESULT]= cmp;
}
cmp->n= args[0]->cols();
cmp->alloc_comparators();
}
/* All DATE/DATETIME fields/functions has the STRING result type. */
if (cmp_type == STRING_RESULT || cmp_type == ROW_RESULT)
{
uint col, cols= args[0]->cols();
for (col= 0; col < cols; col++)
{
bool skip_column= FALSE;
/*
Check that all items to be compared has the STRING result type and at
least one of them is a DATE/DATETIME item.
*/
for (arg= args, arg_end= args + arg_count; arg != arg_end ; arg++)
{
Item *itm= ((cmp_type == STRING_RESULT) ? arg[0] :
arg[0]->element_index(col));
if (itm->result_type() != STRING_RESULT)
{
skip_column= TRUE;
break;
}
else if (itm->is_datetime())
{
datetime_found= TRUE;
/*
Internally all DATE/DATETIME values are converted to the DATETIME
type. So try to find a DATETIME item to issue correct warnings.
*/
if (!date_arg)
date_arg= itm;
else if (itm->field_type() == MYSQL_TYPE_DATETIME)
{
date_arg= itm;
/* All arguments are already checked to have the STRING result. */
if (cmp_type == STRING_RESULT)
break;
}
}
}
if (skip_column)
continue;
if (datetime_found)
{
if (cmp_type == ROW_RESULT)
{
cmp_item **cmp= 0;
if (array)
cmp= ((in_row*)array)->tmp.comparators + col;
else
cmp= ((cmp_item_row*)cmp_items[ROW_RESULT])->comparators + col;
*cmp= new cmp_item_datetime(date_arg);
/* Reset variables for the next column. */
date_arg= 0;
datetime_found= FALSE;
}
else
compare_as_datetime= TRUE;
}
}
}
}
/*
Row item with NULLs inside can return NULL or FALSE =>
they can't be processed as static
*/
if (type_cnt == 1 && const_itm && !nulls_in_row())
{
if (compare_as_datetime)
array= new in_datetime(date_arg, arg_count - 1);
else
{
/*
IN must compare INT columns and constants as int values (the same
way as equality does).
So we must check here if the column on the left and all the constant
values on the right can be compared as integers and adjust the
comparison type accordingly.
*/
if (args[0]->real_item()->type() == FIELD_ITEM &&
thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
thd->lex->sql_command != SQLCOM_SHOW_CREATE &&
cmp_type != INT_RESULT)
{
Item_field *field_item= (Item_field*) (args[0]->real_item());
if (field_item->field->can_be_compared_as_longlong())
{
bool all_converted= TRUE;
for (arg=args+1, arg_end=args+arg_count; arg != arg_end ; arg++)
{
if (!convert_constant_item (thd, field_item, &arg[0]))
all_converted= FALSE;
}
if (all_converted)
cmp_type= INT_RESULT;
}
}
switch (cmp_type) {
case STRING_RESULT:
array=new in_string(arg_count-1,(qsort2_cmp) srtcmp_in,
cmp_collation.collation);
break;
case INT_RESULT:
array= new in_longlong(arg_count-1);
break;
case REAL_RESULT:
array= new in_double(arg_count-1);
break;
case ROW_RESULT:
/*
The row comparator was created at the beginning but only DATETIME
items comparators were initialized. Call store_value() to setup
others.
*/
((in_row*)array)->tmp.store_value(args[0]);
break;
case DECIMAL_RESULT:
array= new in_decimal(arg_count - 1);
break;
default:
DBUG_ASSERT(0);
return;
}
}
if (array && !(thd->is_fatal_error)) // If not EOM
{
uint j=0;
for (uint i=1 ; i < arg_count ; i++)
{
if (!args[i]->null_value) // Skip NULL values
{
array->set(j,args[i]);
j++;
}
else
have_null= 1;
}
if ((array->used_count= j))
array->sort();
}
}
else
{
if (compare_as_datetime)
cmp_items[STRING_RESULT]= new cmp_item_datetime(date_arg);
else
{
for (i= 0; i <= (uint) DECIMAL_RESULT; i++)
{
if (found_types & (1 << i) && !cmp_items[i])
{
if ((Item_result)i == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, arg_count,
MY_COLL_CMP_CONV, 1))
return;
if (!cmp_items[i] && !(cmp_items[i]=
cmp_item::get_comparator((Item_result)i,
cmp_collation.collation)))
return;
}
}
}
}
max_length= 1;
}
void Item_func_in::print(String *str, enum_query_type query_type)
{
str->append('(');
args[0]->print(str, query_type);
if (negated)
str->append(STRING_WITH_LEN(" not"));
str->append(STRING_WITH_LEN(" in ("));
print_args(str, 1, query_type);
str->append(STRING_WITH_LEN("))"));
}
/*
Evaluate the function and return its value.
SYNOPSIS
val_int()
DESCRIPTION
Evaluate the function and return its value.
IMPLEMENTATION
If the array object is defined then the value of the function is
calculated by means of this array.
Otherwise several cmp_item objects are used in order to do correct
comparison of left expression and an expression from the values list.
One cmp_item object correspond to one used comparison type. Left
expression can be evaluated up to number of different used comparison
types. A bit mapped variable value_added_map is used to check whether
the left expression already was evaluated for a particular result type.
Result types are mapped to it according to their integer values i.e.
STRING_RESULT is mapped to bit 0, REAL_RESULT to bit 1, so on.
RETURN
Value of the function
*/
longlong Item_func_in::val_int()
{
cmp_item *in_item;
DBUG_ASSERT(fixed == 1);
uint value_added_map= 0;
if (array)
{
int tmp=array->find(args[0]);
null_value=args[0]->null_value || (!tmp && have_null);
return (longlong) (!null_value && tmp != negated);
}
if ((null_value= args[0]->real_item()->type() == NULL_ITEM))
return 0;
have_null= 0;
for (uint i= 1 ; i < arg_count ; i++)
{
if (args[i]->real_item()->type() == NULL_ITEM)
{
have_null= TRUE;
continue;
}
Item_result cmp_type= item_cmp_type(left_result_type, args[i]->result_type());
in_item= cmp_items[(uint)cmp_type];
DBUG_ASSERT(in_item);
if (!(value_added_map & (1 << (uint)cmp_type)))
{
in_item->store_value(args[0]);
if ((null_value= args[0]->null_value))
return 0;
value_added_map|= 1 << (uint)cmp_type;
}
if (!in_item->cmp(args[i]) && !args[i]->null_value)
return (longlong) (!negated);
have_null|= args[i]->null_value;
}
null_value= have_null;
return (longlong) (!null_value && negated);
}
longlong Item_func_bit_or::val_int()
{
DBUG_ASSERT(fixed == 1);
ulonglong arg1= (ulonglong) args[0]->val_int();
if (args[0]->null_value)
{
null_value=1; /* purecov: inspected */
return 0; /* purecov: inspected */
}
ulonglong arg2= (ulonglong) args[1]->val_int();
if (args[1]->null_value)
{
null_value=1;
return 0;
}
null_value=0;
return (longlong) (arg1 | arg2);
}
longlong Item_func_bit_and::val_int()
{
DBUG_ASSERT(fixed == 1);
ulonglong arg1= (ulonglong) args[0]->val_int();
if (args[0]->null_value)
{
null_value=1; /* purecov: inspected */
return 0; /* purecov: inspected */
}
ulonglong arg2= (ulonglong) args[1]->val_int();
if (args[1]->null_value)
{
null_value=1; /* purecov: inspected */
return 0; /* purecov: inspected */
}
null_value=0;
return (longlong) (arg1 & arg2);
}
Item_cond::Item_cond(THD *thd, Item_cond *item)
:Item_bool_func(thd, item),
abort_on_null(item->abort_on_null),
and_tables_cache(item->and_tables_cache)
{
/*
item->list will be copied by copy_andor_arguments() call
*/
}
void Item_cond::copy_andor_arguments(THD *thd, Item_cond *item)
{
List_iterator_fast<Item> li(item->list);
while (Item *it= li++)
list.push_back(it->copy_andor_structure(thd));
}
bool
Item_cond::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
List_iterator<Item> li(list);
Item *item;
TABLE_LIST *save_emb_on_expr_nest= thd->thd_marker.emb_on_expr_nest;
#ifndef EMBEDDED_LIBRARY
uchar buff[sizeof(char*)]; // Max local vars in function
#endif
not_null_tables_cache= used_tables_cache= 0;
const_item_cache= 1;
if (functype() != COND_AND_FUNC)
thd->thd_marker.emb_on_expr_nest= NULL;
/*
and_table_cache is the value that Item_cond_or() returns for
not_null_tables()
*/
and_tables_cache= ~(table_map) 0;
if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
return TRUE; // Fatal error flag is set!
/*
The following optimization reduces the depth of an AND-OR tree.
E.g. a WHERE clause like
F1 AND (F2 AND (F2 AND F4))
is parsed into a tree with the same nested structure as defined
by braces. This optimization will transform such tree into
AND (F1, F2, F3, F4).
Trees of OR items are flattened as well:
((F1 OR F2) OR (F3 OR F4)) => OR (F1, F2, F3, F4)
Items for removed AND/OR levels will dangle until the death of the
entire statement.
The optimization is currently prepared statements and stored procedures
friendly as it doesn't allocate any memory and its effects are durable
(i.e. do not depend on PS/SP arguments).
*/
while ((item=li++))
{
table_map tmp_table_map;
while (item->type() == Item::COND_ITEM &&
((Item_cond*) item)->functype() == functype() &&
!((Item_cond*) item)->list.is_empty())
{ // Identical function
li.replace(((Item_cond*) item)->list);
((Item_cond*) item)->list.empty();
item= *li.ref(); // new current item
}
if (abort_on_null)
item->top_level_item();
// item can be substituted in fix_fields
if ((!item->fixed &&
item->fix_fields(thd, li.ref())) ||
(item= *li.ref())->check_cols(1))
return TRUE; /* purecov: inspected */
used_tables_cache|= item->used_tables();
if (item->const_item())
and_tables_cache= (table_map) 0;
else
{
tmp_table_map= item->not_null_tables();
not_null_tables_cache|= tmp_table_map;
and_tables_cache&= tmp_table_map;
const_item_cache= FALSE;
}
with_sum_func= with_sum_func || item->with_sum_func;
with_subselect|= item->with_subselect;
if (item->maybe_null)
maybe_null=1;
}
thd->lex->current_select->cond_count+= list.elements;
thd->thd_marker.emb_on_expr_nest= save_emb_on_expr_nest;
fix_length_and_dec();
fixed= 1;
return FALSE;
}
void Item_cond::fix_after_pullout(st_select_lex *new_parent, Item **ref)
{
List_iterator<Item> li(list);
Item *item;
used_tables_cache=0;
const_item_cache=1;
and_tables_cache= ~(table_map) 0; // Here and below we do as fix_fields does
not_null_tables_cache= 0;
while ((item=li++))
{
table_map tmp_table_map;
item->fix_after_pullout(new_parent, li.ref());
item= *li.ref();
used_tables_cache|= item->used_tables();
const_item_cache&= item->const_item();
if (item->const_item())
and_tables_cache= (table_map) 0;
else
{
tmp_table_map= item->not_null_tables();
not_null_tables_cache|= tmp_table_map;
and_tables_cache&= tmp_table_map;
const_item_cache= FALSE;
}
}
}
bool Item_cond::walk(Item_processor processor, bool walk_subquery, uchar *arg)
{
List_iterator_fast<Item> li(list);
Item *item;
while ((item= li++))
if (item->walk(processor, walk_subquery, arg))
return 1;
return Item_func::walk(processor, walk_subquery, arg);
}
/**
Transform an Item_cond object with a transformer callback function.
The function recursively applies the transform method to each
member item of the condition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transformer is applied to the root node
of the Item_cond object.
@param transformer the transformer callback function to be applied to
the nodes of the tree of the object
@param arg parameter to be passed to the transformer
@return
Item returned as the result of transformation of the root node
*/
Item *Item_cond::transform(Item_transformer transformer, uchar *arg)
{
DBUG_ASSERT(!current_thd->is_stmt_prepare());
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
/*
THD::change_item_tree() should be called only if the tree was
really transformed, i.e. when a new item has been created.
Otherwise we'll be allocating a lot of unnecessary memory for
change records at each execution.
*/
if (new_item != item)
current_thd->change_item_tree(li.ref(), new_item);
}
return Item_func::transform(transformer, arg);
}
/**
Compile Item_cond object with a processor and a transformer
callback functions.
First the function applies the analyzer to the root node of
the Item_func object. Then if the analyzer succeeeds (returns TRUE)
the function recursively applies the compile method to member
item of the condition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transformer is applied to the root node
of the Item_cond object.
@param analyzer the analyzer callback function to be applied to the
nodes of the tree of the object
@param[in,out] arg_p parameter to be passed to the analyzer
@param transformer the transformer callback function to be applied to the
nodes of the tree of the object
@param arg_t parameter to be passed to the transformer
@return
Item returned as the result of transformation of the root node
*/
Item *Item_cond::compile(Item_analyzer analyzer, uchar **arg_p,
Item_transformer transformer, uchar *arg_t)
{
if (!(this->*analyzer)(arg_p))
return 0;
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
{
/*
The same parameter value of arg_p must be passed
to analyze any argument of the condition formula.
*/
uchar *arg_v= *arg_p;
Item *new_item= item->compile(analyzer, &arg_v, transformer, arg_t);
if (new_item && new_item != item)
current_thd->change_item_tree(li.ref(), new_item);
}
return Item_func::transform(transformer, arg_t);
}
void Item_cond::traverse_cond(Cond_traverser traverser,
void *arg, traverse_order order)
{
List_iterator<Item> li(list);
Item *item;
switch(order) {
case(PREFIX):
(*traverser)(this, arg);
while ((item= li++))
{
item->traverse_cond(traverser, arg, order);
}
(*traverser)(NULL, arg);
break;
case(POSTFIX):
while ((item= li++))
{
item->traverse_cond(traverser, arg, order);
}
(*traverser)(this, arg);
}
}
/**
Move SUM items out from item tree and replace with reference.
The split is done to get an unique item for each SUM function
so that we can easily find and calculate them.
(Calculation done by update_sum_func() and copy_sum_funcs() in
sql_select.cc)
@param thd Thread handler
@param ref_pointer_array Pointer to array of reference fields
@param fields All fields in select
@note
This function is run on all expression (SELECT list, WHERE, HAVING etc)
that have or refer (HAVING) to a SUM expression.
*/
void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
List<Item> &fields)
{
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
item->split_sum_func2(thd, ref_pointer_array, fields, li.ref(), TRUE);
}
table_map
Item_cond::used_tables() const
{ // This caches used_tables
return used_tables_cache;
}
void Item_cond::update_used_tables()
{
List_iterator_fast<Item> li(list);
Item *item;
used_tables_cache=0;
const_item_cache=1;
while ((item=li++))
{
item->update_used_tables();
used_tables_cache|= item->used_tables();
const_item_cache&= item->const_item();
}
}
void Item_cond::print(String *str, enum_query_type query_type)
{
str->append('(');
List_iterator_fast<Item> li(list);
Item *item;
if ((item=li++))
item->print(str, query_type);
while ((item=li++))
{
str->append(' ');
str->append(func_name());
str->append(' ');
item->print(str, query_type);
}
str->append(')');
}
void Item_cond::neg_arguments(THD *thd)
{
List_iterator<Item> li(list);
Item *item;
while ((item= li++)) /* Apply not transformation to the arguments */
{
Item *new_item= item->neg_transformer(thd);
if (!new_item)
{
if (!(new_item= new Item_func_not(item)))
return; // Fatal OEM error
}
VOID(li.replace(new_item));
}
}
/**
Evaluation of AND(expr, expr, expr ...).
@note
abort_if_null is set for AND expressions for which we don't care if the
result is NULL or 0. This is set for:
- WHERE clause
- HAVING clause
- IF(expression)
@retval
1 If all expressions are true
@retval
0 If all expressions are false or if we find a NULL expression and
'abort_on_null' is set.
@retval
NULL if all expression are either 1 or NULL
*/
longlong Item_cond_and::val_int()
{
DBUG_ASSERT(fixed == 1);
List_iterator_fast<Item> li(list);
Item *item;
null_value= 0;
while ((item=li++))
{
if (!item->val_bool())
{
if (abort_on_null || !(null_value= item->null_value))
return 0; // return FALSE
}
}
return null_value ? 0 : 1;
}
longlong Item_cond_or::val_int()
{
DBUG_ASSERT(fixed == 1);
List_iterator_fast<Item> li(list);
Item *item;
null_value=0;
while ((item=li++))
{
if (item->val_bool())
{
null_value=0;
return 1;
}
if (item->null_value)
null_value=1;
}
return 0;
}
/**
Create an AND expression from two expressions.
@param a expression or NULL
@param b expression.
@param org_item Don't modify a if a == *org_item.
If a == NULL, org_item is set to point at b,
to ensure that future calls will not modify b.
@note
This will not modify item pointed to by org_item or b
The idea is that one can call this in a loop and create and
'and' over all items without modifying any of the original items.
@retval
NULL Error
@retval
Item
*/
Item *and_expressions(Item *a, Item *b, Item **org_item)
{
if (!a)
return (*org_item= (Item*) b);
if (a == *org_item)
{
Item_cond *res;
if ((res= new Item_cond_and(a, (Item*) b)))
{
res->used_tables_cache= a->used_tables() | b->used_tables();
res->not_null_tables_cache= a->not_null_tables() | b->not_null_tables();
}
return res;
}
if (((Item_cond_and*) a)->add((Item*) b))
return 0;
((Item_cond_and*) a)->used_tables_cache|= b->used_tables();
((Item_cond_and*) a)->not_null_tables_cache|= b->not_null_tables();
return a;
}
longlong Item_func_isnull::val_int()
{
DBUG_ASSERT(fixed == 1);
/*
Handle optimization if the argument can't be null
This has to be here because of the test in update_used_tables().
*/
if (!used_tables_cache && !with_subselect)
return cached_value;
return args[0]->is_null() ? 1: 0;
}
longlong Item_is_not_null_test::val_int()
{
DBUG_ASSERT(fixed == 1);
DBUG_ENTER("Item_is_not_null_test::val_int");
if (!used_tables_cache && !with_subselect)
{
owner->was_null|= (!cached_value);
DBUG_PRINT("info", ("cached: %ld", (long) cached_value));
DBUG_RETURN(cached_value);
}
if (args[0]->is_null())
{
DBUG_PRINT("info", ("null"));
owner->was_null|= 1;
DBUG_RETURN(0);
}
else
DBUG_RETURN(1);
}
/**
Optimize case of not_null_column IS NULL.
*/
void Item_is_not_null_test::update_used_tables()
{
if (!args[0]->maybe_null)
{
used_tables_cache= 0; /* is always true */
cached_value= (longlong) 1;
}
else
{
args[0]->update_used_tables();
if (!(used_tables_cache=args[0]->used_tables()) && !with_subselect)
{
/* Remember if the value is always NULL or never NULL */
cached_value= (longlong) !args[0]->is_null();
}
}
}
longlong Item_func_isnotnull::val_int()
{
DBUG_ASSERT(fixed == 1);
return args[0]->is_null() ? 0 : 1;
}
void Item_func_isnotnull::print(String *str, enum_query_type query_type)
{
str->append('(');
args[0]->print(str, query_type);
str->append(STRING_WITH_LEN(" is not null)"));
}
longlong Item_func_like::val_int()
{
DBUG_ASSERT(fixed == 1);
String* res = args[0]->val_str(&cmp.value1);
if (args[0]->null_value)
{
null_value=1;
return 0;
}
String* res2 = args[1]->val_str(&cmp.value2);
if (args[1]->null_value)
{
null_value=1;
return 0;
}
null_value=0;
if (canDoTurboBM)
return turboBM_matches(res->ptr(), res->length()) ? 1 : 0;
return my_wildcmp(cmp.cmp_collation.collation,
res->ptr(),res->ptr()+res->length(),
res2->ptr(),res2->ptr()+res2->length(),
escape,wild_one,wild_many) ? 0 : 1;
}
/**
We can optimize a where if first character isn't a wildcard
*/
Item_func::optimize_type Item_func_like::select_optimize() const
{
if (args[1]->const_item())
{
String* res2= args[1]->val_str((String *)&cmp.value2);
const char *ptr2;
if (!res2 || !(ptr2= res2->ptr()))
return OPTIMIZE_NONE;
if (*ptr2 != wild_many)
{
if (args[0]->result_type() != STRING_RESULT || *ptr2 != wild_one)
return OPTIMIZE_OP;
}
}
return OPTIMIZE_NONE;
}
bool Item_func_like::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if (Item_bool_func2::fix_fields(thd, ref) ||
escape_item->fix_fields(thd, &escape_item))
return TRUE;
if (!escape_item->const_during_execution())
{
my_error(ER_WRONG_ARGUMENTS,MYF(0),"ESCAPE");
return TRUE;
}
if (escape_item->const_item())
{
/* If we are on execution stage */
String *escape_str= escape_item->val_str(&cmp.value1);
if (escape_str)
{
const char *escape_str_ptr= escape_str->ptr();
if (escape_used_in_parsing && (
(((thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES) &&
escape_str->numchars() != 1) ||
escape_str->numchars() > 1)))
{
my_error(ER_WRONG_ARGUMENTS,MYF(0),"ESCAPE");
return TRUE;
}
if (use_mb(cmp.cmp_collation.collation))
{
CHARSET_INFO *cs= escape_str->charset();
my_wc_t wc;
int rc= cs->cset->mb_wc(cs, &wc,
(const uchar*) escape_str_ptr,
(const uchar*) escape_str_ptr +
escape_str->length());
escape= (int) (rc > 0 ? wc : '\\');
}
else
{
/*
In the case of 8bit character set, we pass native
code instead of Unicode code as "escape" argument.
Convert to "cs" if charset of escape differs.
*/
CHARSET_INFO *cs= cmp.cmp_collation.collation;
uint32 unused;
if (escape_str->needs_conversion(escape_str->length(),
escape_str->charset(), cs, &unused))
{
char ch;
uint errors;
uint32 cnvlen= copy_and_convert(&ch, 1, cs, escape_str_ptr,
escape_str->length(),
escape_str->charset(), &errors);
escape= cnvlen ? ch : '\\';
}
else
escape= escape_str_ptr ? *escape_str_ptr : '\\';
}
}
else
escape= '\\';
/*
We could also do boyer-more for non-const items, but as we would have to
recompute the tables for each row it's not worth it.
*/
if (args[1]->const_item() && !use_strnxfrm(collation.collation))
{
String* res2 = args[1]->val_str(&cmp.value2);
if (!res2)
return FALSE; // Null argument
const size_t len = res2->length();
const char* first = res2->ptr();
const char* last = first + len - 1;
/*
len must be > 2 ('%pattern%')
heuristic: only do TurboBM for pattern_len > 2
*/
if (len > MIN_TURBOBM_PATTERN_LEN + 2 &&
*first == wild_many &&
*last == wild_many)
{
const char* tmp = first + 1;
for (; *tmp != wild_many && *tmp != wild_one && *tmp != escape; tmp++) ;
canDoTurboBM = (tmp == last) && !use_mb(args[0]->collation.collation);
}
if (canDoTurboBM)
{
pattern = first + 1;
pattern_len = (int) len - 2;
DBUG_PRINT("info", ("Initializing pattern: '%s'", first));
int *suff = (int*) thd->alloc((int) (sizeof(int)*
((pattern_len + 1)*2+
alphabet_size)));
bmGs = suff + pattern_len + 1;
bmBc = bmGs + pattern_len + 1;
turboBM_compute_good_suffix_shifts(suff);
turboBM_compute_bad_character_shifts();
DBUG_PRINT("info",("done"));
}
}
}
return FALSE;
}
void Item_func_like::cleanup()
{
canDoTurboBM= FALSE;
Item_bool_func2::cleanup();
}
#ifdef USE_REGEX
/**
@brief Compile regular expression.
@param[in] send_error send error message if any.
@details Make necessary character set conversion then
compile regular expression passed in the args[1].
@retval 0 success.
@retval 1 error occurred.
@retval -1 given null regular expression.
*/
int Item_func_regex::regcomp(bool send_error)
{
char buff[MAX_FIELD_WIDTH];
String tmp(buff,sizeof(buff),&my_charset_bin);
String *res= args[1]->val_str(&tmp);
int error;
if (args[1]->null_value)
return -1;
if (regex_compiled)
{
if (!stringcmp(res, &prev_regexp))
return 0;
prev_regexp.copy(*res);
my_regfree(&preg);
regex_compiled= 0;
}
if (cmp_collation.collation != regex_lib_charset)
{
/* Convert UCS2 strings to UTF8 */
uint dummy_errors;
if (conv.copy(res->ptr(), res->length(), res->charset(),
regex_lib_charset, &dummy_errors))
return 1;
res= &conv;
}
if ((error= my_regcomp(&preg, res->c_ptr_safe(),
regex_lib_flags, regex_lib_charset)))
{
if (send_error)
{
(void) my_regerror(error, &preg, buff, sizeof(buff));
my_error(ER_REGEXP_ERROR, MYF(0), buff);
}
return 1;
}
regex_compiled= 1;
return 0;
}
bool
Item_func_regex::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if ((!args[0]->fixed &&
args[0]->fix_fields(thd, args)) || args[0]->check_cols(1) ||
(!args[1]->fixed &&
args[1]->fix_fields(thd, args + 1)) || args[1]->check_cols(1))
return TRUE; /* purecov: inspected */
with_sum_func=args[0]->with_sum_func || args[1]->with_sum_func;
max_length= 1;
decimals= 0;
if (agg_arg_charsets(cmp_collation, args, 2, MY_COLL_CMP_CONV, 1))
return TRUE;
regex_lib_flags= (cmp_collation.collation->state &
(MY_CS_BINSORT | MY_CS_CSSORT)) ?
REG_EXTENDED | REG_NOSUB :
REG_EXTENDED | REG_NOSUB | REG_ICASE;
/*
If the case of UCS2 and other non-ASCII character sets,
we will convert patterns and strings to UTF8.
*/
regex_lib_charset= (cmp_collation.collation->mbminlen > 1) ?
&my_charset_utf8_general_ci :
cmp_collation.collation;
used_tables_cache=args[0]->used_tables() | args[1]->used_tables();
not_null_tables_cache= (args[0]->not_null_tables() |
args[1]->not_null_tables());
const_item_cache=args[0]->const_item() && args[1]->const_item();
if (!regex_compiled && args[1]->const_item())
{
int comp_res= regcomp(TRUE);
if (comp_res == -1)
{ // Will always return NULL
maybe_null=1;
fixed= 1;
return FALSE;
}
else if (comp_res)
return TRUE;
regex_is_const= 1;
maybe_null= args[0]->maybe_null;
}
else
maybe_null=1;
fixed= 1;
return FALSE;
}
longlong Item_func_regex::val_int()
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String tmp(buff,sizeof(buff),&my_charset_bin);
String *res= args[0]->val_str(&tmp);
if ((null_value= (args[0]->null_value ||
(!regex_is_const && regcomp(FALSE)))))
return 0;
if (cmp_collation.collation != regex_lib_charset)
{
/* Convert UCS2 strings to UTF8 */
uint dummy_errors;
if (conv.copy(res->ptr(), res->length(), res->charset(),
regex_lib_charset, &dummy_errors))
{
null_value= 1;
return 0;
}
res= &conv;
}
return my_regexec(&preg,res->c_ptr_safe(),0,(my_regmatch_t*) 0,0) ? 0 : 1;
}
void Item_func_regex::cleanup()
{
DBUG_ENTER("Item_func_regex::cleanup");
Item_bool_func::cleanup();
if (regex_compiled)
{
my_regfree(&preg);
regex_compiled=0;
prev_regexp.length(0);
}
DBUG_VOID_RETURN;
}
#endif /* USE_REGEX */
#ifdef LIKE_CMP_TOUPPER
#define likeconv(cs,A) (uchar) (cs)->toupper(A)
#else
#define likeconv(cs,A) (uchar) (cs)->sort_order[(uchar) (A)]
#endif
/**
Precomputation dependent only on pattern_len.
*/
void Item_func_like::turboBM_compute_suffixes(int *suff)
{
const int plm1 = pattern_len - 1;
int f = 0;
int g = plm1;
int *const splm1 = suff + plm1;
CHARSET_INFO *cs= cmp.cmp_collation.collation;
*splm1 = pattern_len;
if (!cs->sort_order)
{
int i;
for (i = pattern_len - 2; i >= 0; i--)
{
int tmp = *(splm1 + i - f);
if (g < i && tmp < i - g)
suff[i] = tmp;
else
{
if (i < g)
g = i; // g = min(i, g)
f = i;
while (g >= 0 && pattern[g] == pattern[g + plm1 - f])
g--;
suff[i] = f - g;
}
}
}
else
{
int i;
for (i = pattern_len - 2; 0 <= i; --i)
{
int tmp = *(splm1 + i - f);
if (g < i && tmp < i - g)
suff[i] = tmp;
else
{
if (i < g)
g = i; // g = min(i, g)
f = i;
while (g >= 0 &&
likeconv(cs, pattern[g]) == likeconv(cs, pattern[g + plm1 - f]))
g--;
suff[i] = f - g;
}
}
}
}
/**
Precomputation dependent only on pattern_len.
*/
void Item_func_like::turboBM_compute_good_suffix_shifts(int *suff)
{
turboBM_compute_suffixes(suff);
int *end = bmGs + pattern_len;
int *k;
for (k = bmGs; k < end; k++)
*k = pattern_len;
int tmp;
int i;
int j = 0;
const int plm1 = pattern_len - 1;
for (i = plm1; i > -1; i--)
{
if (suff[i] == i + 1)
{
for (tmp = plm1 - i; j < tmp; j++)
{
int *tmp2 = bmGs + j;
if (*tmp2 == pattern_len)
*tmp2 = tmp;
}
}
}
int *tmp2;
for (tmp = plm1 - i; j < tmp; j++)
{
tmp2 = bmGs + j;
if (*tmp2 == pattern_len)
*tmp2 = tmp;
}
tmp2 = bmGs + plm1;
for (i = 0; i <= pattern_len - 2; i++)
*(tmp2 - suff[i]) = plm1 - i;
}
/**
Precomputation dependent on pattern_len.
*/
void Item_func_like::turboBM_compute_bad_character_shifts()
{
int *i;
int *end = bmBc + alphabet_size;
int j;
const int plm1 = pattern_len - 1;
CHARSET_INFO *cs= cmp.cmp_collation.collation;
for (i = bmBc; i < end; i++)
*i = pattern_len;
if (!cs->sort_order)
{
for (j = 0; j < plm1; j++)
bmBc[(uint) (uchar) pattern[j]] = plm1 - j;
}
else
{
for (j = 0; j < plm1; j++)
bmBc[(uint) likeconv(cs,pattern[j])] = plm1 - j;
}
}
/**
Search for pattern in text.
@return
returns true/false for match/no match
*/
bool Item_func_like::turboBM_matches(const char* text, int text_len) const
{
register int bcShift;
register int turboShift;
int shift = pattern_len;
int j = 0;
int u = 0;
CHARSET_INFO *cs= cmp.cmp_collation.collation;
const int plm1= pattern_len - 1;
const int tlmpl= text_len - pattern_len;
/* Searching */
if (!cs->sort_order)
{
while (j <= tlmpl)
{
register int i= plm1;
while (i >= 0 && pattern[i] == text[i + j])
{
i--;
if (i == plm1 - shift)
i-= u;
}
if (i < 0)
return 1;
register const int v = plm1 - i;
turboShift = u - v;
bcShift = bmBc[(uint) (uchar) text[i + j]] - plm1 + i;
shift = max(turboShift, bcShift);
shift = max(shift, bmGs[i]);
if (shift == bmGs[i])
u = min(pattern_len - shift, v);
else
{
if (turboShift < bcShift)
shift = max(shift, u + 1);
u = 0;
}
j+= shift;
}
return 0;
}
else
{
while (j <= tlmpl)
{
register int i = plm1;
while (i >= 0 && likeconv(cs,pattern[i]) == likeconv(cs,text[i + j]))
{
i--;
if (i == plm1 - shift)
i-= u;
}
if (i < 0)
return 1;
register const int v = plm1 - i;
turboShift = u - v;
bcShift = bmBc[(uint) likeconv(cs, text[i + j])] - plm1 + i;
shift = max(turboShift, bcShift);
shift = max(shift, bmGs[i]);
if (shift == bmGs[i])
u = min(pattern_len - shift, v);
else
{
if (turboShift < bcShift)
shift = max(shift, u + 1);
u = 0;
}
j+= shift;
}
return 0;
}
}
/**
Make a logical XOR of the arguments.
If either operator is NULL, return NULL.
@todo
(low priority) Change this to be optimized as: @n
A XOR B -> (A) == 1 AND (B) <> 1) OR (A <> 1 AND (B) == 1) @n
To be able to do this, we would however first have to extend the MySQL
range optimizer to handle OR better.
@note
As we don't do any index optimization on XOR this is not going to be
very fast to use.
*/
longlong Item_cond_xor::val_int()
{
DBUG_ASSERT(fixed == 1);
List_iterator<Item> li(list);
Item *item;
int result=0;
null_value=0;
while ((item=li++))
{
result^= (item->val_int() != 0);
if (item->null_value)
{
null_value=1;
return 0;
}
}
return (longlong) result;
}
/**
Apply NOT transformation to the item and return a new one.
Transform the item using next rules:
@verbatim
a AND b AND ... -> NOT(a) OR NOT(b) OR ...
a OR b OR ... -> NOT(a) AND NOT(b) AND ...
NOT(a) -> a
a = b -> a != b
a != b -> a = b
a < b -> a >= b
a >= b -> a < b
a > b -> a <= b
a <= b -> a > b
IS NULL(a) -> IS NOT NULL(a)
IS NOT NULL(a) -> IS NULL(a)
@endverbatim
@param thd thread handler
@return
New item or
NULL if we cannot apply NOT transformation (see Item::neg_transformer()).
*/
Item *Item_func_not::neg_transformer(THD *thd) /* NOT(x) -> x */
{
return args[0];
}
Item *Item_bool_rowready_func2::neg_transformer(THD *thd)
{
Item *item= negated_item();
return item;
}
/**
a IS NULL -> a IS NOT NULL.
*/
Item *Item_func_isnull::neg_transformer(THD *thd)
{
Item *item= new Item_func_isnotnull(args[0]);
return item;
}
/**
a IS NOT NULL -> a IS NULL.
*/
Item *Item_func_isnotnull::neg_transformer(THD *thd)
{
Item *item= new Item_func_isnull(args[0]);
return item;
}
Item *Item_cond_and::neg_transformer(THD *thd) /* NOT(a AND b AND ...) -> */
/* NOT a OR NOT b OR ... */
{
neg_arguments(thd);
Item *item= new Item_cond_or(list);
return item;
}
Item *Item_cond_or::neg_transformer(THD *thd) /* NOT(a OR b OR ...) -> */
/* NOT a AND NOT b AND ... */
{
neg_arguments(thd);
Item *item= new Item_cond_and(list);
return item;
}
Item *Item_func_nop_all::neg_transformer(THD *thd)
{
/* "NOT (e $cmp$ ANY (SELECT ...)) -> e $rev_cmp$" ALL (SELECT ...) */
Item_func_not_all *new_item= new Item_func_not_all(args[0]);
Item_allany_subselect *allany= (Item_allany_subselect*)args[0];
allany->func= allany->func_creator(FALSE);
allany->all= !allany->all;
allany->upper_item= new_item;
return new_item;
}
Item *Item_func_not_all::neg_transformer(THD *thd)
{
/* "NOT (e $cmp$ ALL (SELECT ...)) -> e $rev_cmp$" ANY (SELECT ...) */
Item_func_nop_all *new_item= new Item_func_nop_all(args[0]);
Item_allany_subselect *allany= (Item_allany_subselect*)args[0];
allany->all= !allany->all;
allany->func= allany->func_creator(TRUE);
allany->upper_item= new_item;
return new_item;
}
Item *Item_func_eq::negated_item() /* a = b -> a != b */
{
return new Item_func_ne(args[0], args[1]);
}
Item *Item_func_ne::negated_item() /* a != b -> a = b */
{
return new Item_func_eq(args[0], args[1]);
}
Item *Item_func_lt::negated_item() /* a < b -> a >= b */
{
return new Item_func_ge(args[0], args[1]);
}
Item *Item_func_ge::negated_item() /* a >= b -> a < b */
{
return new Item_func_lt(args[0], args[1]);
}
Item *Item_func_gt::negated_item() /* a > b -> a <= b */
{
return new Item_func_le(args[0], args[1]);
}
Item *Item_func_le::negated_item() /* a <= b -> a > b */
{
return new Item_func_gt(args[0], args[1]);
}
/**
just fake method, should never be called.
*/
Item *Item_bool_rowready_func2::negated_item()
{
DBUG_ASSERT(0);
return 0;
}
Item_equal::Item_equal(Item_field *f1, Item_field *f2)
: Item_bool_func(), const_item(0), eval_item(0), cond_false(0),
compare_as_dates(FALSE)
{
const_item_cache= 0;
fields.push_back(f1);
fields.push_back(f2);
}
Item_equal::Item_equal(Item *c, Item_field *f)
: Item_bool_func(), eval_item(0), cond_false(0)
{
const_item_cache= 0;
fields.push_back(f);
const_item= c;
compare_as_dates= f->is_datetime();
}
Item_equal::Item_equal(Item_equal *item_equal)
: Item_bool_func(), eval_item(0), cond_false(0)
{
const_item_cache= 0;
List_iterator_fast<Item_field> li(item_equal->fields);
Item_field *item;
while ((item= li++))
{
fields.push_back(item);
}
const_item= item_equal->const_item;
compare_as_dates= item_equal->compare_as_dates;
cond_false= item_equal->cond_false;
}
void Item_equal::compare_const(Item *c)
{
if (compare_as_dates)
{
cmp.set_datetime_cmp_func(this, &c, &const_item);
cond_false= cmp.compare();
}
else
{
Item_func_eq *func= new Item_func_eq(c, const_item);
func->set_cmp_func();
func->quick_fix_field();
cond_false= !func->val_int();
}
if (cond_false)
const_item_cache= 1;
}
void Item_equal::add(Item *c, Item_field *f)
{
if (cond_false)
return;
if (!const_item)
{
DBUG_ASSERT(f);
const_item= c;
compare_as_dates= f->is_datetime();
return;
}
compare_const(c);
}
void Item_equal::add(Item *c)
{
if (cond_false)
return;
if (!const_item)
{
const_item= c;
return;
}
compare_const(c);
}
void Item_equal::add(Item_field *f)
{
fields.push_back(f);
}
uint Item_equal::members()
{
return fields.elements;
}
/**
Check whether a field is referred in the multiple equality.
The function checks whether field is occurred in the Item_equal object .
@param field field whose occurrence is to be checked
@retval
1 if nultiple equality contains a reference to field
@retval
0 otherwise
*/
bool Item_equal::contains(Field *field)
{
List_iterator_fast<Item_field> it(fields);
Item_field *item;
while ((item= it++))
{
if (field->eq(item->field))
return 1;
}
return 0;
}
/**
Join members of another Item_equal object.
The function actually merges two multiple equalities.
After this operation the Item_equal object additionally contains
the field items of another item of the type Item_equal.
If the optional constant items are not equal the cond_false flag is
set to 1.
@param item multiple equality whose members are to be joined
*/
void Item_equal::merge(Item_equal *item)
{
fields.concat(&item->fields);
Item *c= item->const_item;
if (c)
{
/*
The flag cond_false will be set to 1 after this, if
the multiple equality already contains a constant and its
value is not equal to the value of c.
*/
add(c);
}
cond_false|= item->cond_false;
}
/**
Order field items in multiple equality according to a sorting criteria.
The function perform ordering of the field items in the Item_equal
object according to the criteria determined by the cmp callback parameter.
If cmp(item_field1,item_field2,arg)<0 than item_field1 must be
placed after item_fiel2.
The function sorts field items by the bubble sort algorithm.
The list of field items is looked through and whenever two neighboring
members follow in a wrong order they are swapped. This is performed
again and again until we get all members in a right order.
@param compare function to compare field item
@param arg context extra parameter for the cmp function
*/
void Item_equal::sort(Item_field_cmpfunc compare, void *arg)
{
bubble_sort<Item_field>(&fields, compare, arg);
}
/**
Check appearance of new constant items in the multiple equality object.
The function checks appearance of new constant items among
the members of multiple equalities. Each new constant item is
compared with the designated constant item if there is any in the
multiple equality. If there is none the first new constant item
becomes designated.
*/
void Item_equal::update_const()
{
List_iterator<Item_field> it(fields);
Item *item;
while ((item= it++))
{
if (item->const_item())
{
it.remove();
add(item);
}
}
}
bool Item_equal::fix_fields(THD *thd, Item **ref)
{
List_iterator_fast<Item_field> li(fields);
Item_field *item;
not_null_tables_cache= used_tables_cache= 0;
const_item_cache= 0;
while ((item= li++))
{
table_map tmp_table_map;
used_tables_cache|= item->used_tables();
tmp_table_map= item->not_null_tables();
not_null_tables_cache|= tmp_table_map;
if (item->maybe_null)
maybe_null=1;
if (!item->item_equal)
item->item_equal= this;
}
fix_length_and_dec();
fixed= 1;
return 0;
}
void Item_equal::update_used_tables()
{
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache= used_tables_cache= 0;
if ((const_item_cache= cond_false))
return;
const_item_cache= 1;
while ((item=li++))
{
item->update_used_tables();
used_tables_cache|= item->used_tables();
const_item_cache&= item->const_item();
}
}
longlong Item_equal::val_int()
{
Item_field *item_field;
if (cond_false)
return 0;
List_iterator_fast<Item_field> it(fields);
Item *item= const_item ? const_item : it++;
if ((null_value= item->is_null()))
return 0;
eval_item->store_value(item);
while ((item_field= it++))
{
/* Skip fields of non-const tables. They haven't been read yet */
if (item_field->field->table->const_table)
{
if ((null_value= item_field->is_null()) || eval_item->cmp(item_field))
return 0;
}
}
return 1;
}
void Item_equal::fix_length_and_dec()
{
Item *item= get_first(NULL);
eval_item= cmp_item::get_comparator(item->result_type(),
item->collation.collation);
}
bool Item_equal::walk(Item_processor processor, bool walk_subquery, uchar *arg)
{
List_iterator_fast<Item_field> it(fields);
Item *item;
while ((item= it++))
{
if (item->walk(processor, walk_subquery, arg))
return 1;
}
return Item_func::walk(processor, walk_subquery, arg);
}
Item *Item_equal::transform(Item_transformer transformer, uchar *arg)
{
DBUG_ASSERT(!current_thd->is_stmt_prepare());
List_iterator<Item_field> it(fields);
Item *item;
while ((item= it++))
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
/*
THD::change_item_tree() should be called only if the tree was
really transformed, i.e. when a new item has been created.
Otherwise we'll be allocating a lot of unnecessary memory for
change records at each execution.
*/
if (new_item != item)
current_thd->change_item_tree((Item **) it.ref(), new_item);
}
return Item_func::transform(transformer, arg);
}
void Item_equal::print(String *str, enum_query_type query_type)
{
str->append(func_name());
str->append('(');
List_iterator_fast<Item_field> it(fields);
Item *item;
if (const_item)
const_item->print(str, query_type);
else
{
item= it++;
item->print(str, query_type);
}
while ((item= it++))
{
str->append(',');
str->append(' ');
item->print(str, query_type);
}
str->append(')');
}
/*
@brief Get the first equal field of multiple equality.
@param[in] field the field to get equal field to
@details Get the first field of multiple equality that is equal to the
given field. In order to make semi-join materialization strategy work
correctly we can't propagate equal fields from upper select to a
materialized semi-join.
Thus the fields is returned according to following rules:
1) If the given field belongs to a semi-join then the first field in
multiple equality which belong to the same semi-join is returned.
Otherwise NULL is returned.
2) If the given field doesn't belong to a semi-join then
the first field in the multiple equality that doesn't belong to any
semi-join is returned.
If all fields in the equality are belong to semi-join(s) then NULL
is returned.
3) If no field is given then the first field in the multiple equality
is returned without regarding whether it belongs to a semi-join or not.
@retval Found first field in the multiple equality.
@retval 0 if no field found.
*/
Item_field* Item_equal::get_first(Item_field *field)
{
List_iterator<Item_field> it(fields);
Item_field *item;
JOIN_TAB *field_tab;
if (!field)
return fields.head();
/*
Of all equal fields, return the first one we can use. Normally, this is the
field which belongs to the table that is the first in the join order.
There is one exception to this: When semi-join materialization strategy is
used, and the given field belongs to a table within the semi-join nest, we
must pick the first field in the semi-join nest.
Example: suppose we have a join order:
ot1 ot2 SJ-Mat(it1 it2 it3) ot3
and equality ot2.col = it1.col = it2.col
If we're looking for best substitute for 'it2.col', we should pick it1.col
and not ot2.col.
eliminate_item_equal() also has code that deals with equality substitution
in presense of SJM nests.
*/
field_tab= field->field->table->reginfo.join_tab;
TABLE_LIST *emb_nest= field->field->table->pos_in_table_list->embedding;
if (emb_nest && emb_nest->sj_mat_info && emb_nest->sj_mat_info->is_used)
{
/*
It's a field from an materialized semi-join. We can substitute it only
for a field from the same semi-join.
*/
JOIN_TAB *first= field_tab;
JOIN *join= field_tab->join;
int tab_idx= field_tab - field_tab->join->join_tab;
DBUG_ASSERT(join->join_tab[tab_idx].table->map &
emb_nest->sj_inner_tables);
/* Find the first table of this semi-join nest */
for (int i= tab_idx-1; i >= (int)join->const_tables; i--)
{
if (join->join_tab[i].table->map & emb_nest->sj_inner_tables)
first= join->join_tab + i;
else
// Found first tab that doesn't belong to current SJ.
break;
}
/* Find an item to substitute for. */
while ((item= it++))
{
if (item->field->table->reginfo.join_tab >= first)
{
/*
If we found given field then return NULL to avoid unnecessary
substitution.
*/
return (item != field) ? item : NULL;
}
}
}
else
{
#if 0
/*
The field is not in SJ-Materialization nest. We must return the first
field that's not embedded in a SJ-Materialization nest.
Example: suppose we have a join order:
SJ-Mat(it1 it2) ot1 ot2
and equality ot2.col = ot1.col = it2.col
If we're looking for best substitute for 'ot2.col', we should pick ot1.col
and not it2.col, because when we run a join between ot1 and ot2
execution of SJ-Mat(...) has already finished and we can't rely on the
value of it*.*.
psergey-fix-fix: ^^ THAT IS INCORRECT ^^. Pick the first, whatever that
is.
*/
while ((item= it++))
{
TABLE_LIST *emb_nest= item->field->table->pos_in_table_list->embedding;
if (!emb_nest || !emb_nest->sj_mat_info ||
!emb_nest->sj_mat_info->is_used)
{
return item;
}
}
#endif
return fields.head();
}
// Shouldn't get here.
DBUG_ASSERT(0);
return NULL;
}
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