技術標籤：MYSQL

資料表內容：

SELECT * FROM runoob.runoob_tbl;

統計runoob_title重複次數大於1的個數（HAVING子句設定重複數大於1。）：

select count(runoob_title) as repetitions, runoob_title,runoob_author from runoob_tbl group by runoob_title having repetitions>1;

過濾重複runoob_title重複的列：

select runoob_title,runoob_author submisson_data from runoob_tbl group by runoob_title;
 

刪除重複資料：

create table tmp select * from runoob_tbl group by runoob_title;
drop table runoob_tbl;
alter table tmp rename to runoob_tbl;