Syntax:
DROP TRIGGER [IF EXISTS] [schema_name.]trigger_name

This statement drops a trigger. The schema (database) name is optional.
If the schema is omitted, the trigger is dropped from the default
schema. DROP TRIGGER was added in MySQL 5.0.2. Its use requires the
SUPER privilege.

Use IF EXISTS to prevent an error from occurring for a trigger that
does not exist. A NOTE is generated for a non-existent trigger when
using IF EXISTS. See [HELP SHOW WARNINGS]. The IF EXISTS clause was
added in MySQL 5.0.32.

URL: http://dev.mysql.com/doc/refman/5.0/en/drop-trigger.html

