Releases the lock named by the string
str that was obtained with GET_LOCK(). Returns 1 if the lock was released, 0 if the
lock was not established by this thread (in which case the lock is not
NULL if the named lock did not exist. The
lock does not exist if it was never obtained by a call to
GET_LOCK() or if it has previously been released.
MariaDB until 10.0.1
GET_LOCK() released the existing lock, if any. Since 10.0.2 this does not happen, because multiple locks are allowed.
str is case insensitive. If
str is an empty string or
NULL and does nothing.
The DO statement is convenient to use with