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有表a,b
需要创建视图c以实现c中的字段anum,bnum分别为a,b中的记录数目
谢谢
select (select count(*) from a) anum,(select count(*) from b) bnum from dual
create view c
as
select (select count(*) from a ) anum,(select count(*) from b ) bnum from dual
SQL> create view test_cou as
2 SELECT A.COU AS A表条数, B.COU AS B表条数
3 FROM (SELECT 1 AS id, COUNT(*) AS cou
4 FROM AAA_CSDN_1) A,
5 (SELECT 1 AS id, COUNT(*) AS cou
6 FROM AAAA_CSDN_2) B
7 WHERE A.ID = B.ID;
视图已建立。
SQL> select * from test_cou;
A表条数 B表条数
---------- ----------
5 3
SQL>
2楼的方法即间接又明了。
N个表的记录数都可以。DUAL是一个只有一行数据的系统表
