MySQL觸發器在創建時，報語法錯的問題

delimiter $$
create trigger trg_delete_on_users before DELETE on users
for each row 
begin
    delete from authorities where username = old.username ;
    delete from user_action where user_name = old.username ;
end $$
delimiter ;

開頭要使用的 delimiter $$ 來定義$$爲分隔符，在末尾再把分隔符恢復爲分號。不然，解釋器遇到分號，就認爲你SQL完結了，而後就報語法錯了，坑爹不？？