Oracle数据库删除两表中相同数据的方法

SQL> create table a (
2　bm char(4), --编码
3　mc varchar2(20) --名称
4　)
5　/

SQL> insert into a values('1111','1111');
SQL> insert into a values('1112','1111');
SQL> insert into a values('1113','1111');
SQL> insert into a values('1114','1111');
SQL> insert into a values('1115','1111');

SQL> create table b as select * from a where 1=2;

SQL> insert into b values('1111','1111');
SQL> insert into b values('1112','1111');
SQL> insert into b values('1113','1111');
SQL> insert into b values('1114','1111');

SQL> commit;

SQL> select * from a;

BM　 MC
---- --------------------
1111 1111
1112 1111
1113 1111
1114 1111
1115 1111

SQL> select * from b;

BM　 MC
---- --------------------
1111 1111
1112 1111
1113 1111
1114 1111

SQL> delete from a where exists (select 'X' from b where a.bm=b.bm and a.mc=b.mc);

SQL> delete from a where (bm,mc) in (select bm,mc from b);

删除4个记录.

SQL> select * from a;

BM　 MC
---- --------------------
1115 1111