This problem occured for statements like `INSERT INTO t1 SELECT 1`,
which do not have tables in the SELECT part. In such scenarios
SELECT_LEX::insert_tables was not properly set at `setup_tables()`,
and this led to either incorrect execution or a crash
Reviewer: Oleksandr Byelkin <sanja@mariadb.com>
regression from MDEV-29540 / 8c38939369.
INSERT SELECT errors needed to be unconditionally ignored.
As this touches the CREATE .. SELECT functionality, show
the equalivent test there.
This bug manifested itself for INSERT...SELECT and DELETE statements whose
WHERE condition used an IN/ANY/ALL predicand or a EXISTS predicate with
such grouping subquery that:
- its GROUP BY clause could be eliminated,
- the GROUP clause contained a subquery over a mergeable derived table
referencing the updated table.
The bug ultimately caused a server crash when the prepare phase of the
statement processing was executed. This happened after removal redundant
subqueries used in the eliminated GROUP BY clause from the statement tree.
The function that excluded the subqueries from the did not do it properly.
As a result the specification of any derived table contained in a removed
subquery was not marked as excluded.
Approved by Oleksandr Byelkin <sanja@mariadb.com>
1. For INSERT..SELECT statements: don't include table/view the data
is inserted into in the list of leaf tables
2. Remove duplicated and dead code related to table_count
