Mysql刪除重複的資料的方法

這篇文章主要介紹了Mysql刪除重複的資料Mysql資料去重複,需要的朋友可以參考下

MySQL資料庫中查詢重複資料

select * from employee group by emp_name having count (*)>1;

Mysql  查詢可以刪除的重複資料

select t1.* from employee t1 where (t1.emp_name) in (select t4.emp_name from (select t2.emp_name from employee t2 group by t2.emp_name having count(*)>1) t4) and t1.emp_id not in (select t5.emp_id from (select min(t3.emp_id) as emp_id from employee t3 group by t3.emp_name having count(*)>1) t5);

Mysql  刪除重複的資料

delete t1 from employee t1 where (t1.emp_name) in (select t4.emp_name from (select t2.emp_name from employee t2 group by t2.emp_name having count(*)>1) t4) and t1.emp_id not in (select t5.emp_id from (select min(t3.emp_id) as emp_id from employee t3 group by t3.emp_name having count(*)>1) t5);

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