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oracle数据表删除重复数据
阅读量:590 次
发布时间:2019-03-11

本文共 1295 字,大约阅读时间需要 4 分钟。

去重查询:

SQL> select * from flash_tbl;

 

ID VL

---------- --

10 I

11 J

12 K

13 L

14 M

15 N

16 O

17 P

18 Q

19 R

20 S

 

ID VL

---------- --

1 /

2 A

3 B

4 C

5 D

6 E

7 F

8 G

9 H

1 /

2 A

 

ID VL

---------- --

3 B

4 C

5 D

6 E

7 F

8 G

9 H

1 /

2 A

3 B

4 C

 

ID VL

---------- --

5 D

6 E

7 F

8 G

9 H

 

38 rows selected.

SQL> select distinct id,vl from flash_tbl;

ID VL

---------- --

11 J

14 M

7 F

8 G

20 S

4 C

5 D

12 K

16 O

17 P

1 /

 

ID VL

---------- --

10 I

13 L

2 A

3 B

15 N

18 Q

6 E

9 H

19 R

20 rows selected.

删除重复数据(两种方式)

SQL> select * from flash_tbl a where rowid !=(select max(rowid) from flash_tbl b where a.id=b.id);    -----查出重复数据

SQL> delete from flash_tbl a where rowid !=(select max(rowid) from flash_tbl b where a.id=b.id);      -----删掉重复数据

-----------------------------------------------------------------------------------------------------------------------------------

SQL> select * from flash_tbl where Id in (select Id from flash_tbl group by Id having count(Id) > 1);    -----查出重复数据

SQL> delete from flash_tbl where Id in (select Id from flash_tbl group by Id having count(Id) > 1) and rowid not in (select min(rowid) from flash_tbl group by Id having count(Id)>1);     -----删掉重复数据

------------------------------------------------------------------------------------------------------------------------------------

 

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