sql删除重复数据只保留一条

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

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 PID NOT IN (SELECT MIN(PID) 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 PID not in (select min(PID) 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 PID not in (select min(PID) from 表 group by Id,seq having count(*)>1)