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Comments - Datetime behavior in MariaDB vs MySQL

5 years, 11 months ago Ian Gilfillan
Re: Datetime behavior in MariaDB vs MySQL [Answer]

MariaDB considers all badly formatted strings as '0000-00-00 00:00:00' for comparison purposes. Current versions of MySQL are inconsistent, in that they handle constants one way, and non-constants another way.

Consider the following example from MySQL, with confusing results:

SET sql_mode='';
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (a FLOAT, b DATETIME, c TIME, d VARCHAR(10));
INSERT INTO t1 VALUES ( 111.222, '23Apr75', '05May99', 'a');
SELECT * FROM t1 WHERE b='31Jan1999';
SELECT * FROM t1 WHERE b=IF(RAND(),'31Jan1999','31Jan1999');

SELECT * FROM t1 WHERE b='31Jan1999';
Empty set, 2 warnings (0.00 sec)

SELECT * FROM t1 WHERE b=IF(RAND(),'31Jan1999','31Jan1999');
+---------+---------------------+----------+------+
| a       | b                   | c        | d    |
+---------+---------------------+----------+------+
| 111.222 | 0000-00-00 00:00:00 | 00:00:05 | a    |
+---------+---------------------+----------+------+
1 row in set, 1 warning (0.00 sec)
 
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