MySQL 5.7 Release Notes
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.
TRIGGER privilege for
the table associated with the trigger.
IF EXISTS to prevent an error from
occurring for a trigger that does not exist. A
NOTE is generated for a nonexistent trigger
IF EXISTS. See
Section 188.8.131.52, “SHOW WARNINGS Statement”.
Triggers for a table are also dropped if you drop the table.