[MDEV-8694] Wrong result for SELECT..WHERE a NOT LIKE 'a ' AND a='a' - Jira

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This script:

DROP TABLE IF EXISTS t1;

CREATE TABLE t1 (a VARCHAR(10) COLLATE latin1_bin);

INSERT INTO t1 VALUES ('a'),('a ');

SELECT a, LENGTH(a) FROM t1 WHERE a NOT LIKE 'a ';

returns one row:

+------+-----------+

| a    | LENGTH(a) |

+------+-----------+

| a    |         1 |

+------+-----------+

Now if I make the condition even stronger:

SELECT a, LENGTH(a) FROM t1 WHERE a NOT LIKE 'a ' AND a='a';

it erroneously returns 2 rows:

+------+-----------+

| a    | LENGTH(a) |

+------+-----------+

| a    |         1 |

| a    |         2 |

+------+-----------+

The problem happens in equal fields propagation.

WHERE a NOT LIKE 'a ' AND a='a'

gets rewritten to

WHERE 'a' NOT LIKE 'a ' AND a='a'

then LIKE gets removed from the condition.

blocks

MDEV-8728 Fix a number of problems in equal field and equal expression propagation

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