- 论坛徽章:
- 0
|
select sql_id from test5
SQL_ID
----------
1
2
select sql_id from test6
SQL_ID
----------
1
2
select nvl(ta.v1,0)+nvl(tb.v1,0)
from (select sql_id as v1 from test5) ta
full outer join
(select sql_id as v1 from test6) tb
on (1=1);
result:
NVL(TA.V1,0)+NVL(TB.V1,0)
-------------------------
2
3
3
4
truncate table test6;(清空表test6的数据)
select nvl(ta.v1,0)+nvl(tb.v1,0)
from (select sql_id as v1 from test5) ta
full outer join
(select sql_id as v1 from test6) tb
on (1=1);
result:
NVL(TA.V1,0)+NVL(TB.V1,0)
-------------------------
1
2
这个sql语句会产生cartesian效果,如果要用于测试,注意数据量。。。
如果要实现你的功能,一定要有两张表的连接条件,防止产生cartesian
你现在的需求还不是很明晰。 |
|