MySQL不能用select和子查詢指定目標表並選擇

Question

我有這個疑問：

UPDATE answers AS aa SET aa.question_id=(SELECT q.id FROM question AS q WHERE q.question LIKE (SELECT a.question_prev FROM answers AS a)) 

錯誤：

mysql cant specify target table

而且無法弄清楚如何編輯它的工作

Answer 1

試試這個，

UPDATE answers a 
     INNER JOIN question b 
      ON b.question = a.question_prev 
SET  a.question_id = b.id 

執行語句前請先備份。