Mysql 查詢表中重複資料和刪除表中重複的資料
阿新 • • 發佈:2019-01-06
1、根據指定條件查詢表中的重複記錄
select * from t_official_sys_user
where USER_NAME in (select USER_NAME from (select USER_NAME from t_official_sys_user group by USER_NAME having count(USER_NAME) > 1) as temtalble );
sql分析:
查詢使用者表: t_official_sys_user ,統計 USER_NAME這個欄位判斷大於一條記錄以上的記錄進行分組,然後放到一張臨時表 tamtalbe . 查詢USER_NAME在臨時表中的記錄為重複記錄.
2、刪除重複記錄
delete from t_official_sys_user
where USER_NAME IN(select USER_NAME from ( SELECT USER_NAME FROM t_official_sys_user group by `USER_NAME` having count(1) > 1) as temtable );