Regular Expression MySQL

mysql>
mysql>
mysql> SELECT '0m' REGEXP '^([[:digit:]]+|[[:alpha:]]+)$';
+---------------------------------------------+
| '0m' REGEXP '^([[:digit:]]+|[[:alpha:]]+)$' |
+---------------------------------------------+
|                                           0 |
+---------------------------------------------+
1 row in set (0.00 sec)
mysql>