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Fixed bug#16377: result of DATE/TIME functions were compared as strings which

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can lead to a wrong result.

All date/time functions has the STRING result type thus their results are
compared as strings. The string date representation allows a user to skip 
some of leading zeros. This can lead to wrong comparison result if a date/time 
function result is compared to such a string constant.

The idea behind this bug fix is to compare results of date/time functions
and data/time constants as ints, because that date/time representation is 
more exact. To achieve this the agg_cmp_type() is changed to take in the
account that a date/time field or an date/time item should be compared 
as ints.

This bug fix is partially back ported from 5.0.

The agg_cmp_type() function now accepts THD as one of parameters. 
In addition, it now checks if a date/time field/function is present in the
list. If so, it tries to coerce all constants to INT to make date/time
comparison return correct result. The field for the constant coercion is
taken from the Item_field or constructed from the Item_func. In latter case
the constructed field will be freed after conversion of all constant items.
Otherwise the result is same as before - aggregated with help of the
item_cmp_type() function.

From the Item_func_between::fix_length_and_dec() function removed the part
which was converting date/time constants to int if possible. Now this is 
done by the agg_cmp_type() function.

The new function result_as_longlong() is added to the Item class. 
It indicates that the item is a date/time item and result of it can be
compared as int. Such items are date/time fields/functions.

Correct val_int() methods are implemented for classes Item_date_typecast, 
Item_func_makedate, Item_time_typecast, Item_datetime_typecast. All these
classes are derived from Item_str_func and Item_str_func::val_int() converts
its string value to int without regard to the date/time type of these items.

Arg_comparator::set_compare_func() and Arg_comparator::set_cmp_func()
functions are changed to substitute result type of an item with the INT_RESULT
if the item is a date/time item and another item is a constant. This is done
to get a correct result of comparisons like date_time_function() = string_constant.


mysql-test/r/cast.result:
  Fixed wrong test case result after bug fix#16377.
sql/item_timefunc.h:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  The result_as_longlong() function is set to return TRUE for these classes:
  Item_date, Item_date_func, Item_func_curtime, Item_func_sec_to_time,
  Item_date_typecast, Item_time_typecast, Item_datetime_typecast,
  Item_func_makedate.
sql/item_timefunc.cc:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.Correct val_int() methods are implemented for classes Item_date_typecast, 
  Item_func_makedate, Item_time_typecast, Item_datetime_typecast.
sql/item_cmpfunc.h:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  Arg_comparator::set_compare_func() and Arg_comparator::set_cmp_func()
  functions are changed to substitute result type of an item with the INT_RESULT
  if the item is a date/time item and another item is a constant.
sql/field.cc:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  Field::set_warning(), Field::set_datetime_warning() now use current_thd to get thd if table isn't set.
sql/item_cmpfunc.cc:
  Fixed bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
  The agg_cmp_type() function now accepts THD as one of parameters. 
  In addition, it now checks if a date/time field/function is present in the
  list. If so, it tries to coerce all constants to INT to make date/time
  comparison return correct result. The field for the constant coercion is
  taken from the Item_field or constructed from the Item_func. In latter case
  the constructed field will be freed after conversion of all constant items.
  Otherwise the result is same as before - aggregated with help of the
  item_cmp_type() function.
sql/item.h:
  The new function result_as_longlong() is added to the Item class. 
  It indicates that the item is a date/time item and result of it can be
  compared as int. Such items are date/time fields/functions.
mysql-test/t/func_time.test:
  Added test case fot bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
mysql-test/r/func_time.result:
  Added test case fot bug#16377: result of DATE/TIME functions were compared as strings which
  can lead to a wrong result.
This commit is contained in:
unknown 2006-06-13 19:09:24 +04:00
parent a9824f263d
commit 47311e8e87
9 changed files with 293 additions and 42 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
mysql-test/r/cast.result
View file

@ -192,7 +192,7 @@ cast("2001-1-1" as datetime) = "2001-01-01 00:00:00"
1
select cast("1:2:3" as TIME) = "1:02:03";
cast("1:2:3" as TIME) = "1:02:03"
0
1
select cast(NULL as DATE);
cast(NULL as DATE)
NULL

41
mysql-test/r/func_time.result
View file

@ -630,3 +630,44 @@ select monthname(str_to_date(null, '%m')), monthname(str_to_date(null, '%m')),
monthname(str_to_date(1, '%m')), monthname(str_to_date(0, '%m'));
monthname(str_to_date(null, '%m')) monthname(str_to_date(null, '%m')) monthname(str_to_date(1, '%m')) monthname(str_to_date(0, '%m'))
NULL NULL January NULL
create table t1(f1 date, f2 time, f3 datetime);
insert into t1 values ("2006-01-01", "12:01:01", "2006-01-01 12:01:01");
insert into t1 values ("2006-01-02", "12:01:02", "2006-01-02 12:01:02");
select f1 from t1 where f1 between "2006-1-1" and 20060101;
f1
2006-01-01
select f1 from t1 where f1 between "2006-1-1" and "2006.1.1";
f1
2006-01-01
select f1 from t1 where date(f1) between "2006-1-1" and "2006.1.1";
f1
2006-01-01
select f2 from t1 where f2 between "12:1:2" and "12:2:2";
f2
12:01:02
select f2 from t1 where time(f2) between "12:1:2" and "12:2:2";
f2
12:01:02
select f3 from t1 where f3 between "2006-1-1 12:1:1" and "2006-1-1 12:1:2";
f3
2006-01-01 12:01:01
select f3 from t1 where timestamp(f3) between "2006-1-1 12:1:1" and "2006-1-1 12:1:2";
f3
2006-01-01 12:01:01
select f1 from t1 where "2006-1-1" between f1 and f3;
f1
2006-01-01
select f1 from t1 where "2006-1-1" between date(f1) and date(f3);
f1
2006-01-01
select f1 from t1 where "2006-1-1" between f1 and 'zzz';
f1
Warnings:
Warning 1292 Truncated incorrect date value: 'zzz'
select f1 from t1 where makedate(2006,1) between date(f1) and date(f3);
f1
2006-01-01
select f1 from t1 where makedate(2006,2) between date(f1) and date(f3);
f1
2006-01-02
drop table t1;

20
mysql-test/t/func_time.test
View file

@ -322,4 +322,24 @@ select last_day('2005-01-00');
select monthname(str_to_date(null, '%m')), monthname(str_to_date(null, '%m')),
monthname(str_to_date(1, '%m')), monthname(str_to_date(0, '%m'));
#
# Bug#16377 result of DATE/TIME functions were compared as strings which
# can lead to a wrong result.
#
create table t1(f1 date, f2 time, f3 datetime);
insert into t1 values ("2006-01-01", "12:01:01", "2006-01-01 12:01:01");
insert into t1 values ("2006-01-02", "12:01:02", "2006-01-02 12:01:02");
select f1 from t1 where f1 between "2006-1-1" and 20060101;
select f1 from t1 where f1 between "2006-1-1" and "2006.1.1";
select f1 from t1 where date(f1) between "2006-1-1" and "2006.1.1";
select f2 from t1 where f2 between "12:1:2" and "12:2:2";
select f2 from t1 where time(f2) between "12:1:2" and "12:2:2";
select f3 from t1 where f3 between "2006-1-1 12:1:1" and "2006-1-1 12:1:2";
select f3 from t1 where timestamp(f3) between "2006-1-1 12:1:1" and "2006-1-1 12:1:2";
select f1 from t1 where "2006-1-1" between f1 and f3;
select f1 from t1 where "2006-1-1" between date(f1) and date(f3);
select f1 from t1 where "2006-1-1" between f1 and 'zzz';
select f1 from t1 where makedate(2006,1) between date(f1) and date(f3);
select f1 from t1 where makedate(2006,2) between date(f1) and date(f3);
drop table t1;
# End of 4.1 tests

16
sql/field.cc
View file

@ -6841,7 +6841,11 @@ create_field::create_field(Field *old_field,Field *orig_field)
bool
Field::set_warning(const uint level, const uint code, int cuted_increment)
{
THD *thd= table->in_use;
/*
If this field was created only for type conversion purposes it
will have table == NULL.
*/
THD *thd= table ? table->in_use : current_thd;
if (thd->count_cuted_fields)
{
thd->cuted_fields+= cuted_increment;
@ -6876,7 +6880,8 @@ Field::set_datetime_warning(const uint level, const uint code,
timestamp_type ts_type, int cuted_increment)
{
if (set_warning(level, code, cuted_increment))
make_truncated_value_warning(table->in_use, str, str_length, ts_type);
make_truncated_value_warning(table ? table->in_use : current_thd,
str, str_length, ts_type);
}
@ -6905,8 +6910,8 @@ Field::set_datetime_warning(const uint level, const uint code,
{
char str_nr[22];
char *str_end= longlong10_to_str(nr, str_nr, -10);
make_truncated_value_warning(table->in_use, str_nr, str_end - str_nr,
ts_type);
make_truncated_value_warning(table ? table->in_use : current_thd,
str_nr, str_end - str_nr, ts_type);
}
}
@ -6935,7 +6940,8 @@ Field::set_datetime_warning(const uint level, const uint code,
/* DBL_DIG is enough to print '-[digits].E+###' */
char str_nr[DBL_DIG + 8];
uint str_len= my_sprintf(str_nr, (str_nr, "%g", nr));
make_truncated_value_warning(table->in_use, str_nr, str_len, ts_type);
make_truncated_value_warning(table ? table->in_use : current_thd,
str_nr, str_len, ts_type);
}
}

16
sql/item.h
View file

@ -327,6 +327,14 @@ public:
cleanup();
delete this;
}
/*
result_as_longlong() must return TRUE for Items representing DATE/TIME
functions and DATE/TIME table fields.
Those Items have result_type()==STRING_RESULT (and not INT_RESULT), but
their values should be compared as integers (because the integer
representation is more precise than the string one).
*/
virtual bool result_as_longlong() { return FALSE; }
};
@ -450,6 +458,10 @@ public:
Item *get_tmp_table_item(THD *thd);
void cleanup();
inline uint32 max_disp_length() { return field->max_length(); }
bool result_as_longlong()
{
return field->can_be_compared_as_longlong();
}
friend class Item_default_value;
friend class Item_insert_value;
friend class st_select_lex_unit;
@ -973,6 +985,10 @@ public:
}
Item *real_item() { return *ref; }
void print(String *str);
bool result_as_longlong()
{
return (*ref)->result_as_longlong();
}
};

154
sql/item_cmpfunc.cc
View file

@ -25,6 +25,8 @@
#include <m_ctype.h>
#include "sql_select.h"
static bool convert_constant_item(THD *thd, Field *field, Item **item);
static Item_result item_store_type(Item_result a,Item_result b)
{
if (a == STRING_RESULT || b == STRING_RESULT)
@ -64,6 +66,7 @@ static void agg_result_type(Item_result *type, Item **items, uint nitems)
SYNOPSIS:
agg_cmp_type()
thd thread handle
type [out] the aggregated type
items array of items to aggregate the type from
nitems number of items in the array
@ -78,24 +81,133 @@ static void agg_result_type(Item_result *type, Item **items, uint nitems)
If all items are constants the type will be aggregated from all items.
If there are some non-constant items then only types of non-constant
items will be used for aggregation.
If there are DATE/TIME fields/functions in the list and no string
fields/functions in the list then:
The INT_RESULT type will be used for aggregation instead of orginal
result type of any DATE/TIME field/function in the list
All constant items in the list will be converted to a DATE/TIME using
found field or result field of found function.
Implementation notes:
The code is equvalent to:
1. Check the list for presense of a STRING field/function.
Collect the is_const flag.
2. Get a Field* object to use for type coercion
3. Perform type conversion.
1 and 2 are implemented in 2 loops. The first searches for a DATE/TIME
field/function and checks presense of a STRING field/function.
The second loop works only if a DATE/TIME field/function is found.
It checks presense of a STRING field/function in the rest of the list.
TODO
1) The current implementation can produce false comparison results for
expressions like:
date_time_field BETWEEN string_field_with_dates AND string_constant
if the string_constant will omit some of leading zeroes.
In order to fully implement correct comparison of DATE/TIME the new
DATETIME_RESULT result type should be introduced and agg_cmp_type()
should return the DATE/TIME field used for the conversion. Later
this field can be used by comparison functions like Item_func_between to
convert string values to ints on the fly and thus return correct results.
This modification will affect functions BETWEEN, IN and CASE.
2) If in the list a DATE field/function and a DATETIME field/function
are present in the list then the first found field/function will be
used for conversion. This may lead to wrong results and probably should
be fixed.
*/
static void agg_cmp_type(Item_result *type, Item **items, uint nitems)
static void agg_cmp_type(THD *thd, Item_result *type, Item **items, uint nitems)
{
uint i;
type[0]= items[0]->result_type();
Item::Type res;
char *buff= NULL;
uchar null_byte;
Field *field= NULL;
/* Search for date/time fields/functions */
for (i= 0; i < nitems; i++)
{
if (!items[i]->result_as_longlong())
{
/* Do not convert anything if a string field/function is present */
if (!items[i]->const_item() && items[i]->result_type() == STRING_RESULT)
{
i= nitems;
break;
}
continue;
}
if ((res= items[i]->real_item()->type()) == Item::FIELD_ITEM)
{
field= ((Item_field *)items[i]->real_item())->field;
break;
}
else if (res == Item::FUNC_ITEM)
{
field= items[i]->tmp_table_field_from_field_type(0);
if (field)
buff= alloc_root(thd->mem_root, field->max_length());
if (!buff || !field)
{
if (field)
delete field;
if (buff)
my_free(buff, MYF(MY_WME));
field= 0;
}
else
field->move_field(buff, &null_byte, 0);
break;
}
}
if (field)
{
/* Check the rest of the list for presense of a string field/function. */
for (i++ ; i < nitems; i++)
{
if (!items[i]->const_item() && items[i]->result_type() == STRING_RESULT &&
!items[i]->result_as_longlong())
{
field= 0;
break;
}
}
}
/* Reset to 0 on first occurence of non-const item. 1 otherwise */
bool is_const= items[0]->const_item();
/*
If the first item is a date/time function then its result should be
compared as int
*/
if (field)
{
/* Suppose we are comparing dates and some non-constant items are present. */
type[0]= INT_RESULT;
is_const= 0;
}
else
type[0]= items[0]->result_type();
for (i= 1 ; i < nitems ; i++)
for (i= 0; i < nitems ; i++)
{
if (!items[i]->const_item())
{
type[0]= is_const ? items[i]->result_type() :
item_cmp_type(type[0], items[i]->result_type());
Item_result result= field && items[i]->result_as_longlong() ?
INT_RESULT : items[i]->result_type();
type[0]= is_const ? result : item_cmp_type(type[0], result);
is_const= 0;
}
else if (is_const)
type[0]= item_cmp_type(type[0], items[i]->result_type());
else if (field)
convert_constant_item(thd, field, &items[i]);
}
if (res == Item::FUNC_ITEM && field)
{
delete field;
my_free(buff, MYF(MY_WME));
}
}
@ -929,31 +1041,9 @@ void Item_func_between::fix_length_and_dec()
*/
if (!args[0] || !args[1] || !args[2])
return;
agg_cmp_type(&cmp_type, args, 3);
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV))
return;
/*
Make a special case of compare with date/time and longlong fields.
They are compared as integers, so for const item this time-consuming
conversion can be done only once, not for every single comparison
*/
if (args[0]->type() == FIELD_ITEM)
{
Field *field=((Item_field*) args[0])->field;
if (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,&args[1]))
cmp_type=INT_RESULT; // Works for all types.
if (convert_constant_item(thd, field,&args[2]))
cmp_type=INT_RESULT; // Works for all types.
}
}
agg_cmp_type(thd, &cmp_type, args, 3);
if (cmp_type == STRING_RESULT)
agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV);
}
@ -1477,7 +1567,7 @@ void Item_func_case::fix_length_and_dec()
for (nagg= 0; nagg < ncases/2 ; nagg++)
agg[nagg+1]= args[nagg*2];
nagg++;
agg_cmp_type(&cmp_type, agg, nagg);
agg_cmp_type(current_thd, &cmp_type, agg, nagg);
if ((cmp_type == STRING_RESULT) &&
agg_arg_charsets(cmp_collation, agg, nagg, MY_COLL_CMP_CONV))
return;
@ -1958,7 +2048,7 @@ void Item_func_in::fix_length_and_dec()
uint const_itm= 1;
THD *thd= current_thd;
agg_cmp_type(&cmp_type, args, arg_count);
agg_cmp_type(thd, &cmp_type, args, arg_count);
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, arg_count, MY_COLL_CMP_CONV))

14
sql/item_cmpfunc.h
View file

@ -43,8 +43,11 @@ public:
int set_compare_func(Item_bool_func2 *owner, Item_result type);
inline int set_compare_func(Item_bool_func2 *owner_arg)
{
return set_compare_func(owner_arg, item_cmp_type((*a)->result_type(),
(*b)->result_type()));
Item_result ar= (*a)->result_as_longlong() && (*b)->const_item() ?
INT_RESULT : (*a)->result_type();
Item_result br= (*b)->result_as_longlong() && (*a)->const_item() ?
INT_RESULT : (*b)->result_type();
return set_compare_func(owner_arg, item_cmp_type(ar, br));
}
inline int set_cmp_func(Item_bool_func2 *owner_arg,
Item **a1, Item **a2,
@ -57,8 +60,11 @@ public:
inline int set_cmp_func(Item_bool_func2 *owner_arg,
Item **a1, Item **a2)
{
return set_cmp_func(owner_arg, a1, a2, item_cmp_type((*a1)->result_type(),
(*a2)->result_type()));
Item_result ar= (*a1)->result_as_longlong() && (*a2)->const_item() ?
INT_RESULT : (*a1)->result_type();
Item_result br= (*a2)->result_as_longlong() && (*a1)->const_item() ?
INT_RESULT : (*a2)->result_type();
return set_cmp_func(owner_arg, a1, a2, item_cmp_type(ar, br));
}
inline int compare() { return (this->*func)(); }

60
sql/item_timefunc.cc
View file

@ -2306,6 +2306,20 @@ String *Item_datetime_typecast::val_str(String *str)
}
longlong Item_datetime_typecast::val_int()
{
DBUG_ASSERT(fixed == 1);
TIME ltime;
if (get_arg0_date(&ltime,1))
{
null_value= 1;
return 0;
}
return TIME_to_ulonglong_datetime(&ltime);
}
bool Item_time_typecast::get_time(TIME *ltime)
{
bool res= get_arg0_time(ltime);
@ -2320,6 +2334,17 @@ bool Item_time_typecast::get_time(TIME *ltime)
}
longlong Item_time_typecast::val_int()
{
TIME ltime;
if (get_time(&ltime))
{
null_value= 1;
return 0;
}
return ltime.hour * 10000L + ltime.minute * 100 + ltime.second;
}
String *Item_time_typecast::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
@ -2359,6 +2384,14 @@ String *Item_date_typecast::val_str(String *str)
return 0;
}
longlong Item_date_typecast::val_int()
{
DBUG_ASSERT(fixed == 1);
TIME ltime;
if (args[0]->get_date(&ltime, TIME_FUZZY_DATE))
return 0;
return (longlong) (ltime.year * 10000L + ltime.month * 100 + ltime.day);
}
/*
MAKEDATE(a,b) is a date function that creates a date value
@ -2395,6 +2428,33 @@ err:
}
longlong Item_func_makedate::val_int()
{
DBUG_ASSERT(fixed == 1);
TIME l_time;
long daynr= (long) args[1]->val_int();
long yearnr= (long) args[0]->val_int();
long days;
if (args[0]->null_value || args[1]->null_value ||
yearnr < 0 || daynr <= 0)
goto err;
days= calc_daynr(yearnr,1,1) + daynr - 1;
/* Day number from year 0 to 9999-12-31 */
if (days >= 0 && days < MAX_DAY_NUMBER)
{
null_value=0;
get_date_from_daynr(days,&l_time.year,&l_time.month,&l_time.day);
return (longlong) (l_time.year * 10000L + l_time.month * 100 + l_time.day);
}
err:
null_value= 1;
return 0;
}
void Item_func_add_time::fix_length_and_dec()
{
enum_field_types arg0_field_type;

12
sql/item_timefunc.h
View file

@ -339,6 +339,7 @@ public:
{
return (new Field_date(maybe_null, name, t_arg, &my_charset_bin));
}
bool result_as_longlong() { return TRUE; }
};
@ -354,6 +355,7 @@ public:
{
return (new Field_datetime(maybe_null, name, t_arg, &my_charset_bin));
}
bool result_as_longlong() { return TRUE; }
};
@ -383,6 +385,7 @@ public:
TIME representation using UTC-SYSTEM or per-thread time zone.
*/
virtual void store_now_in_TIME(TIME *now_time)=0;
bool result_as_longlong() { return TRUE; }
};
@ -588,6 +591,7 @@ public:
{
return (new Field_time(maybe_null, name, t_arg, &my_charset_bin));
}
bool result_as_longlong() { return TRUE; }
};
/*
@ -715,6 +719,8 @@ public:
max_length= 10;
maybe_null= 1;
}
bool result_as_longlong() { return TRUE; }
longlong val_int();
};
@ -731,6 +737,8 @@ public:
{
return (new Field_time(maybe_null, name, t_arg, &my_charset_bin));
}
bool result_as_longlong() { return TRUE; }
longlong val_int();
};
@ -746,6 +754,8 @@ public:
{
return (new Field_datetime(maybe_null, name, t_arg, &my_charset_bin));
}
bool result_as_longlong() { return TRUE; }
longlong val_int();
};
class Item_func_makedate :public Item_str_func
@ -764,6 +774,8 @@ public:
{
return (new Field_date(maybe_null, name, t_arg, &my_charset_bin));
}
bool result_as_longlong() { return TRUE; }
longlong val_int();
};