SQL removal of duplicate data

1. Add test data with stored procedures

CREATE PROCEDURE newprocedure ()
BEGIN
DECLARE i INT;
SET I=1;
While i<50000 do
INSERT into User_new (id,name,phone,sex) VALUES (i,i,i,i);
SET i = i + 1;
END while;
END;

Two inserts, modifies the ID value of the stored procedure once, then obtains the Name,phone,sex duplicate 5W data (time is limited, does not operate the larger quantity)

2, Data de-weight

Common ways:

One

Update user_new set data_status=0 where ID not in

(select Max (ID) as ID from t_testr_res_indicate GROUP by Name,phone,sex
);

Second, the volume of repeated data use less

Update user_new set data_status=0 where ID not in

(select Max (ID) as ID from user_new GROUP by Name,phone,sex have Count (*) >1
) and

ID in

(select ID from user_new GROUP by Name,phone,sex have Count (*) >1
) ;

SQL removal of duplicate data