sql delete duplicate rows

 SELECT *from user_info;

 

-- filter duplicate rows by single field

SELECT *from user_info WHERE NAME in ( SELECT NAME from user_info GROUP BY NAME HAVING COUNT(NAME)>1);

 

 -- 删除重复行，保留id最小的数据
SELECT *from user_info WHERE 
NAME in ( SELECT NAME from user_info GROUP BY NAME HAVING COUNT(NAME)>1)
AND id NOT in ( SELECT min(id) from user_info GROUP BY NAME HAVING COUNT(NAME)>1);

 -- Multi-field judgment repetition

SELECT * from user_info WHERE (name,school) in ( SELECT name,school from user_info group by name,school HAVING COUNT(*)>1);