MDEV-36389 Incorrect query results for an indexed text column #4124
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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.
DaveGosselin-MariaDB
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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:
Internally, he 'abc' IN subquery condition becomes the constant condition:
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.