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MDEV-36389 Incorrect query results for an indexed text column

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Fixes a scenario where an IN subquery returned the wrong result
because the pushed WHERE clause was not retained for downstream
result filtering.  For example:
  CREATE TABLE t1 (c1 TEXT, UNIQUE (c1(1)));
  INSERT INTO t1 (c1) VALUES ('a');
  SELECT 'abc' IN (SELECT c1 FROM t1);
Internally, he 'abc' IN subquery condition becomes the constant
condition:
  'abc' = t1.c1 or t1.c1 is null
Prior to this patch, this condition was incorrectly removed when
converting the subquery engine to an index lookup-based engine.
Now eligible conditions are preserved during such engine rewrites.
This commit is contained in:
Sergei Petrunia
2025-07-23 15:40:53 +03:00
committed by Dave Gosselin
parent 3109d994eb
commit a52362b90c
21 changed files with 201 additions and 119 deletions
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2
mysql-test/suite/gcol/r/gcol_select_myisam.result
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@@ -1121,7 +1121,7 @@ id select_type table type possible_keys key key_len ref rows Extra
EXPLAIN SELECT * FROM t2 AS t1 WHERE b NOT IN (SELECT b FROM t1 FORCE INDEX(b));
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 system NULL NULL NULL NULL 1
2 SUBQUERY t1 index_subquery b b 5 func 3 Using index; Full scan on NULL key
2 DEPENDENT SUBQUERY t1 index_subquery b b 5 func 3 Using index; Using where; Full scan on NULL key
DROP TABLE t1;
DROP TABLE t2, t3;
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