because internally setup_wild() adjusts select_lex->with_wild directly
anyway, so there is no reason to pretend that the number of '*' may be
anything else but select_lex->with_wild
And don't update select_lex->item_list, because fields can come
from anywhere and don't necessarily have to be copied into select_lex.
Shift-Reduce conflicts prevented parsing some queries with subqueries that
used set operations when the subqueries occurred in expressions or in IN
predicands.
The grammar rules for query expression were transformed in order to avoid
these conflicts. New grammar rules employ an idea taken from MySQL 8.0.
Step #2: "[ORDER BY ...] LIMIT n" should not prevent EXISTS-to-IN
conversion, as long as
- the LIMIT clause doesn't have OFFSET
- the LIMIT is not "LIMIT 0".
Step 1: Removal of ORDER BY [LIMIT] from the subquery should be done
earlier and for broader class of subqueries.
The rewrite was done in Item_in_subselect::select_in_like_transformer(),
but this had problems:
- It didn't cover EXISTS subqueries
- It covered IN-subqueries, but was done after the semi-join transformation
was considered inapplicable, because ORDER BY was present.
Remaining issue:
- EXISTS->IN transformation happens before
check_and_do_in_subquery_rewrites() is called, so it is still prevented
by the present ORDER BY.
query with VALUES()
A table value constructor can be used in all contexts where a select
can be used. In particular an ORDER BY clause or a LIMIT clause or both
of them can be attached to a table value constructor to produce a new
query. Unfortunately execution of such queries was not supported.
This patch fixes the problem.
`sel->quick' failure in JOIN::make_range_rowid_filters upon query
with rowid_filter=ON
Index ranges can be defined using conditions with inexpensive subqueries.
Such a subquery is evaluated when some representation of a possible range
sequence is built. After the evaluation the JOIN structure of the subsquery is distroyed.
Any attempt to build the above representation may fail because the
function that checks whether a subquery is inexpensive in some cases uses
the join structure of the subquery.
When a range rowid filter is built by a range sequence constructed out of
a range condition that uses an inexpensive subquery the representation of
the the sequence is built twice. Building the second representation fails
due to the described problem with the execution of Item_subselect::is_expensive().
The function was corrected to return the result of the last its invocation
if the Item_subselect object has been already evaluated.
