Oracle 刪除重複數據只留一條

查詢及刪除重複記錄的SQL語句

一、查找表中多餘的重複記錄，重複記錄是根據單個字段（Id）來判斷

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

二、刪除表中多餘的重複記錄，重複記錄是根據單個字段（Id）來判斷，只留有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);

三、查找表中多餘的重複記錄（多個字段）

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

四、刪除表中多餘的重複記錄（多個字段），只留有rowid最小的記錄

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)

五、查找表中多餘的重複記錄（多個字段），不包含rowid最小的記錄

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)