MySQL Duplicate record query Delete method

1, look for redundant records in the table, duplicate records are based on a single field (Peopleid) to determine
SELECT * from People
where Peopleid in (select Peopleid from People GROUP by Peopleid have count (Peopleid) > 1)

2, delete redundant records in the table, duplicate records are based on a single field (Peopleid) to judge, leaving only the smallest ROWID records
Delete from people
where Peopleid in (select Peopleid from People GROUP by Peopleid have count (Peopleid) > 1)
and rowID not in (select min (rowid) from people GROUP by Peopleid have Count (Peopleid) >1)

3. Find redundant duplicate records (multiple fields) in the table
SELECT * from C_yyt
WHERE (Elon in (select Elon from C_yyt GROUP by Elon, WD has COUNT (*) > 1)) and (WD in (SELECT WD from C_yyt GROUP by Elon, WD has COUNT (*) > 1))

4. Delete extra duplicate records (multiple fields) in the table, leaving only the record with ROWID minimum
Delete from Vitae a
where (A.PEOPLEID,A.SEQ) in (select Peopleid,seq from Vitae GROUP by PEOPLEID,SEQ have count (*) > 1)
and rowID not in (select min (rowid) from Vitae GROUP by PEOPLEID,SEQ have Count (*) >1)

5. Find redundant duplicate records (multiple fields) in the table, not including the smallest ROWID records
SELECT * FROM Vitae a
where (A.PEOPLEID,A.SEQ) in (select Peopleid,seq from Vitae GROUP by PEOPLEID,SEQ have

COUNT (*) > 1)
and rowID not in (select min (rowid) from Vitae GROUP by PEOPLEID,SEQ have Count (*) >1)

6. Delete duplicate data

1, the smallest ID in the duplicate data is found, and inserted into a temporary table;
2, and then delete the duplicate data through the table association;
INSERT into Line_pass_init select min (id) from Tt_rps_line_passzone_info_init GROUP by plan_send_batch_dt,line_id, Passid,order_flag having Count (*) >1
#性能低
DELETE from Tt_rps_line_passzone_info_init where ID not EXISTS (SELECT ID from line_pass_init);
#性能高
Delete from Tt_rps_line_passzone_info_init a where is not exists (select 1 from line_pass_stor_init b where a.id=b.id);

MySQL Duplicate record query Delete method