MySQL Delete duplicate records

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 and 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;

Ref

Http://stackoverflow.com/questions/3311903/remove-duplicate-rows-in-mysql

Http://stackoverflow.com/questions/4685173/delete-all-duplicate-rows-except-for-one-in-mysql

Http://stackoverflow.com/questions/14046355/how-do-i-delete-all-the-duplicate-records-in-a-mysql-table-without-temp-tables

Http://www.databasejournal.com/features/mysql/article.php/10897_2201621_2/Deleting-Duplicate-Rows-in-a-MySQL-Database.htm

MySQL Delete duplicate records