MySQL in a Nutshell

Name

RELEASE_LOCK( )

Synopsis

RELEASE_LOCK(string)

This function releases a lock created by GET_LOCK(). The name of the lock is given in parentheses. If successful, 1 is returned; if unsuccessful, 0 is returned. If the lock specified does not exist, NULL is returned.

SELECT RELEASE_LOCK('my_lock');
+-------------------------+
| RELEASE_LOCK('my_lock') |
+-------------------------+
|                       1 |
+-------------------------+

As an alternative to using SELECT, you can use DO; no results are returned.

DO RELEASE_LOCK('my_lock');