1、查找多餘的重複記錄，重複記錄是根據單個字段識別
select * from 表 where id in (select id from 表 group by id having count(id) > 1)
2、刪除多餘的重複記錄，重複記錄是根據單個字段識別，只保留rowid最小的記錄
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、查找多餘的重複記錄（多個字段）
select * from 表 a where (a.column1,a.column2) in(select column1,column2 from 表 group by column1,column2 having count(*) > 1)
4、刪除多餘的重複記錄（多個字段），只保留rowid最小的記錄
delete from 表 a where (a.column1,a.column2) in (select column1,column2 from 表 group by column1,column2 having count(*) > 1) and rowid not in (select min(rowid) from 表 group by column1,column2 having count(*)>1)
5、查找多餘的重複記錄（多個字段），排除rowid最小的記錄
select * from 表 a where (a.column1,a.column2) in (select column1,column2 from 表 group by column1,column2 having count(*) > 1) and rowid not in (select min(rowid) from 表 group by column1,column2 having count(*)>1)
