Mega Code Archive
Regular expressions do not match NULL values This is true both for REGEXP and for NOT REGEXP
mysql>
mysql>
mysql> SELECT NULL REGEXP '.*', NULL NOT REGEXP '.*';
+------------------+----------------------+
| NULL REGEXP '.*' | NULL NOT REGEXP '.*' |
+------------------+----------------------+
| NULL | NULL |
+------------------+----------------------+
1 row in set (0.00 sec)
mysql>