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.
Added test cases for bug #7351.
item_cmpfunc.cc:
Fixed bug #7351: incorrect result for a query with a
subquery returning empty set.
If in the predicate v IN (SELECT a FROM t WHERE cond)
v is null, then the result of the predicate is either
INKNOWN or FALSE. It is FALSE if the subquery returns
an empty set.
item_subselect.cc:
Fixed bug #7351: incorrect result for a query with a
subquery returning empty set.
The problem was due to not a quite legal transformation
for 'IN' subqueries. A subquery containing a predicate
of the form
v IN (SELECT a FROM t WHERE cond)
was transformed into
EXISTS(SELECT a FROM t WHERE cond AND (a=v OR a IS NULL)).
Yet, this transformation is valid only if v is not null.
If v is null, then, in the case when
(SELECT a FROM t WHERE cond) returns an empty set the value
of the predicate is FALSE, otherwise the result of the
predicate is INKNOWN.
The fix resolves this problem by changing the result
of the transformation to
EXISTS(SELECT a FROM t WHERE cond AND (v IS NULL OR (a=v OR a IS NULL)))
in the case when v is nullable.
The new transformation prevents applying the lookup
optimization for IN subqueries. To make it still
applicable we have to introduce guarded access methods.
to behave well on 5.0 tables (well now you can't use tables from 4.1
and 5.0 with 4.0 because former use utf8, but still it is nice to have
similar code in acl_init() and replace_user_table()).
This also will make such GRANTs working in 5.0 (they are broken now).
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.)
