如何觸發刪除記錄

Question

我的觸發看起來像這樣：

CREATE TRIGGER addATicket AFTER INSERT ON ticket FOR EACH ROW BEGIN 

declare numTicket int(2) default 0; 
select count(*) into numTicket from ticket 
    where (ticket.ticket_id != new.ticket_id) 
    and (ticket.seat_code = new.seat_code); 

if (numTicket > 0) then 
    delete from ticket where ticket_id= new.ticket_id; 
end if;END 

但我的工作臺捕獲了一個錯誤：

Error Code: 1442. Can't update table 'ticket' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.

我怎樣才能解決這個問題。請給我一個幫助。

Answer 1

這很可能是因爲您的主要INSERT查詢正在觸發TRIGGER在該表上持有行級鎖，因此您的觸發器也抱怨同樣的情況。

很可能你想把AFTER INSERT ON ticket的觸發定義改爲BEFORE INSERT ON ticket（我的意思是用BEFORE TRIGGER代替）。

看到一個幾乎相同的帖子在這裏

MySql Error: Can't update table in stored function/trigger because it is already used by statement which invoked this stored function/trigger