Syntax
------

DROP PROCEDURE [IF EXISTS] sp_name

Description
-----------

This statement is used to drop a stored procedure. That is, the specified
routine is removed from the server along with all privileges specific to the
procedure. You must have the ALTER ROUTINE privilege for the routine. If the
automatic_sp_privileges server system variable is set, that privilege and
EXECUTE are granted automatically to the routine creator - see Stored Routine
Privileges.

The IF EXISTS clause is a MySQL/MariaDB extension. It prevents an error from
occurring if the procedure or function does not exist. A NOTE is produced that
can be viewed with SHOW WARNINGS.

While this statement takes effect immediately, threads which are executing a
procedure can continue execution.

Examples
--------

DROP PROCEDURE simpleproc;

IF EXISTS:

DROP PROCEDURE simpleproc;
ERROR 1305 (42000): PROCEDURE test.simpleproc does not exist

DROP PROCEDURE IF EXISTS simpleproc;
Query OK, 0 rows affected, 1 warning (0.00 sec)

SHOW WARNINGS;
+-------+------+------------------------------------------+
| Level | Code | Message                                  |
+-------+------+------------------------------------------+
| Note  | 1305 | PROCEDURE test.simpleproc does not exist |
+-------+------+------------------------------------------+

URL: https://mariadb.com/kb/en/drop-procedure/