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  1. MariaDB Server
  2. MDEV-8766

Wrong result for SELECT..WHERE LENGTH(time_column)=8 AND time_column=TIMESTAMP'2001-01-01 10:20:31'

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    Description

      SET timestamp=UNIX_TIMESTAMP('2001-01-01 01:02:03');
      		 
      DROP TABLE IF EXISTS t1;
      		 
      CREATE TABLE t1 (a TIME);
      		 
      INSERT INTO t1 VALUES ('10:20:31'),('-10:20:31');
      		 
      SELECT * FROM t1 WHERE a=TIMESTAMP'2001-01-01 10:20:31';
      		 
      SELECT * FROM t1 WHERE LENGTH(a)=8;
      		 
      SELECT * FROM t1 WHERE LENGTH(a)=8 AND a=TIMESTAMP'2001-01-01 10:20:31';

      In the above script the first and the second SELECT queries correctly return one row, the third SELECT query returns erroneously no rows.

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          Bug - A problem which impairs or prevents the functions of the product. MDEV-8728 Fix a number of problems in equal field and equal expression propagation

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Activity

            bar Alexander Barkov added a comment -

            MySQL-5.7.8 does not support propagation in this case:

            explain extended SELECT * FROM t1 WHERE LENGTH(a)=8 AND a=TIMESTAMP'2001-01-01 10:20:31';
            		 
            SHOW WARNINGS;
            		 

            +---------+------+----------------------------------------------------------------------------------------------------------------------------------------+
            		 
            | Level   | Code | Message                                                                                                                                |
            		 
            +---------+------+----------------------------------------------------------------------------------------------------------------------------------------+
            		 
            | Warning | 1681 | 'EXTENDED' is deprecated and will be removed in a future release.                                                                      |
            		 
            | Note    | 1003 | /* select#1 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where ((length(`test`.`t1`.`a`) = 8) and (`test`.`t1`.`a` = '10:20:31')) |
            		 
            +---------+------+----------------------------------------------------------------------------------------------------------------------------------------+

            bar Alexander Barkov added a comment - MySQL-5.7.8 does not support propagation in this case: explain extended SELECT * FROM t1 WHERE LENGTH(a)=8 AND a=TIMESTAMP'2001-01-01 10:20:31'; SHOW WARNINGS; +---------+------+----------------------------------------------------------------------------------------------------------------------------------------+ | Level | Code | Message | +---------+------+----------------------------------------------------------------------------------------------------------------------------------------+ | Warning | 1681 | 'EXTENDED' is deprecated and will be removed in a future release. | | Note | 1003 | /* select#1 */ select `test`.`t1`.`a` AS `a` from `test`.`t1` where ((length(`test`.`t1`.`a`) = 8) and (`test`.`t1`.`a` = '10:20:31')) | +---------+------+----------------------------------------------------------------------------------------------------------------------------------------+

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              bar Alexander Barkov
              bar Alexander Barkov
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                Updated:
                Resolved:

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