[MySql] 刪除重複資料

有兩種方式   一種是直接對該重複資料的欄位建立uniqle index

ALTER IGNORE TABLE `資料表名稱` ADD UNIQUE INDEX(`欄位1`,`欄位2`...);

還有另一種個人覺得比較好的做法  可以去決定要保留哪一筆資料下來

delete from table_name where id in (select id from people group by id having count(*) > 1)

或是用

DELETE FROM table_name WHERE pk NOT IN (SELECT MAX(pk) From table_name GROUP BY id)