SQL-删除重复数据

查询及删除重复记录的SQL语句

1、查找表中多余的重复记录,重复记录是根据单个字段(Id)来判断

select * from 表 where Id in (select Id from 表 group byId having count(Id) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(Id)来判断,只留有rowid最小的记录

DELETE from 表 
WHERE (id) IN 
( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) 
AND ROWID NOT IN (SELECT MIN(ROWID) 
FROM 表 GROUP BY id HAVING COUNT(*) > 1);

3、查找表中多余的重复记录(多个字段)

select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*) > 1)

4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录

delete from 表 a 
where (a.Id,a.seq) in (select Id,seq 
from 表 group by Id,seq having count( * ) > 1) 
and 
rowid not in (select min(rowid) 
from 表 group by Id,seq having count( * )>1)

5、查找表中多余的重复记录(多个字段),不包含rowid最小的记录

select * from 表 a 
where (a.Id,a.seq) in 
(select Id,seq from 表 group by Id,seq having count( * ) > 1) 
and 
rowid not in (select min(rowid) 
from 表 group by Id,seq having count( * )>1)
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