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.
Conversion from int and real numbers to UCS2 didn't work fine:
CONVERT(100, CHAR(50) UNICODE)
CONVERT(103.9, CHAR(50) UNICODE)
The problem appeared because numbers have binary charset, so,
simple charset recast binary->ucs2 was performed
instead of real conversion.
Fixed to make numbers pretend to be non-binary.
fix for bug #15828 after review
doing val_str now before testing of null value secures the function for null values returned by dynamic functions - the fix before was incomplete andy covered constant null values
Removed wrong fix for bug #14009 (use of abs() on null value causes problems with filesort)
Mark that add_time(), time_diff() and str_to_date() can return null values
collation
By default constant strings in second parameter of date_time() have case
insensitive collation. Because of this expressions date_format(f,'%m') and
date_format(f,'%M') wrongly becomes equal, which results in choosing wrong
column to sort by.
Now if second parameter of date_format() is constant then it's collation is
changed to case sensitive.
Ensure that 'null_value' is not accessed before val() is called in FIELD() functions
Fixed initialization of key maps. This fixes some problems with keys when you have more than 64 keys
Fixed that ROLLUP don't always create a temporary table. This fix ensures that func_gconcat.test results are now predictable
result" (and similar bug in ADDTIME/SUBTIME).
Both Item_func_add_time/Item_func_timediff::val_str() now use
calc_time_diff() function which was backported from 5.0 (and which
was was fixed to properly handle microseconds part of its second
argument). Also now we correctly set sign of result in case when
first argument is negative and second is positive.
does not work well together". Now using simplier and more correct
implementation of st_lex::unlink_first_table()/link_first_table_back()
(It also nicely handles case when global table list is created because
of implictly used time zone tables). (2nd attempt)
Fix for bug #7705 "CONVERT_TZ() crashes with subquery/WHERE on index
column". Implemented new approach for caching objects for constant
time zone arguments. Now instead of determining whenever these arguments
are constants and performing time zone lookup at fix_fields() stage, we
do it on first get_date() invocation.
Cleanup of global @@time_zone variable handling.
When we cast datetime value to DATE (TIME) type we should throw away its
time (date) part. This was not done properly if CAST() function was used
in datetime expressions.
STR_TO_DATE() function if there is another format specifier after %f
in format string". Also small cleanup of STR_TO_DATE() implementation.
(After review version.)
Now thd->mem_root is a pointer to thd->main_mem_root and THR_MALLOC is a pointer to thd->mem_root.
This gives us the following benefits:
- Allow us to easily detect if arena has already been swapped before (this fixes a bug in setup_conds() where arena was swaped twice in some cases)
- Faster swaps of arenas (as we don't have to copy the whole MEM_ROOT)
- We don't anymore have to call my_pthread_setspecific_ptr(THR_MALLOC,...) to change where memory is alloced. Now it's enough to set thd->mem_root
statements and negative time/date values".
The bug was in wrong sprintf format used in the client library.
The fix moves TIME -> string conversion functions to sql-common and
utilized them in the client library.
column types TIMESTAMP is NOT NULL by default, so in order to have
TIMESTAMP column holding NULL valaues you have to specify NULL as
one of its attributes (this needed for backward compatibility).
Main changes:
Replaced TABLE::timestamp_default_now/on_update_now members with
TABLE::timestamp_auto_set_type flag which is used everywhere
for determining if we should auto-set value of TIMESTAMP field
during this operation or not. We are also use Field_timestamp::set_time()
instead of handler::update_timestamp() in handlers.
Instead of trying to open time zone tables during calculation of CONVERT_TZ() function
or setting of @@time_zone variable we should open and lock them with the rest of
statement's table (so we should add them to global table list) and after that use such
pre-opened tables for loading info about time zones.
work (prepared statements)" and after-review fixes:
- str_to_TIME renamed to str_to_datetime to pair with str_to_time
- functions str_to_time and str_to_TIME moved to sql-common
- send_data_str now supports MYSQL_TYPE_TIME, MYSQL_TIME_DATE,
MYSQL_TIME_DATETIME types of user input buffers.
- few more comments in the client library
- a test case added.
Added basic per-thread time zone functionality (based on public
domain elsie-code). Now user can select current time zone
(from the list of time zones described in system tables).
All NOW-like functions honor this time zone, values of TIMESTAMP
type are interpreted as values in this time zone, so now
our TIMESTAMP type behaves similar to Oracle's TIMESTAMP WITH
LOCAL TIME ZONE (or proper PostgresSQL type).
WL#1266 "CONVERT_TZ() - basic time with time zone conversion
function".
Fixed problems described in Bug #2336 (Different number of warnings
when inserting bad datetime as string or as number). This required
reworking of datetime realted warning hadling (they now generated
at Field object level not in conversion functions).
Optimization: Now Field class descendants use table->in_use member
instead of current_thd macro.
