如何刪除SQL中的重複行？

Question

我想刪除使用SQL的重複行，同時留下其中一行。

我想刪除重複的行從被稱爲表「A」由的表：

A.AID, A.BID, A.AName, A.AType, A.APrice. 

在這個表中我有很多的所有數據的重複行正好相隔相同來自A.ID.

我想創建一個查詢，它將查找重複項，然後刪除重複項，確保其中一行被留下。我正在使用phpMyAdmin和MySQL。

Answer 1

DELETE FROM member 
WHERE id IN (SELECT * 
      FROM (SELECT id FROM member 
        GROUP BY member_id, quiz_num, question_num, answer_num HAVING (COUNT(*) > 1) 
       ) AS A 
      ); 

use group by and count

Answer 2

DELETE FROM 
    YourTable 
WHERE 
    AID NOT IN (SELECT 
        MAX(AID) 
       FROM 
        YourTable 
       GROUP BY 
        BID , 
        AName , 
        AType , 
        APrice); 

Answer 3

考慮下面的查詢，這將刪除所有重複的行和阻止任何未來的重複行。

ALTER IGNORE TABLE A ADD UNIQUE INDEX index_name (A.AID, A.BID, A.AName, A.AType, A.APrice);