mysql删除重复记录

发布时间：2023-05-05 13:00:15 所属栏目：MsSql教程来源：

导读：Solution 1：

Add Unique Index on your table:

ALTER IGnorE TABLE `TableA`
ADD UNIQUE INDEX (`member_id`, `quiz_num`, `question_num`, `answer_num`);
Solution 2：

Add primry key in your tab

Solution 1：

Add Unique Index on your table:

ALTER IGnorE TABLE `TableA`
ADD UNIQUE INDEX (`member_id`, `quiz_num`, `question_num`, `answer_num`);
Solution 2：

Add primry key in your table then you can easily remove duplicates from your table using below query:

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
);

Solution 3：

SELECT disTINCT * INTO TableA_Verify FROM TableA;
DROP TABLE TableA;
RENAME TABLE TableA_Verify TO TableA;

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