-
本版专家分：0结帖率 75.76% -
有三张表：
a ： b: c:
id name id age1 id age2
1 jia 1 15 2 26
2 liu 3 23 4 20
3 wang
4 zhao
怎样做一个视图如下
id name age
1 jia 15
2 liu 26
3 wang 23
4 zhao 20![]()
-
本版专家分：31579 -
select a.id,a.name,b.age1 as age
from
(select id,age1 from b union all
select id,age2 from c) b
join a on a.id=b.id
-
本版专家分：1198 -
create view test as
select a.id,a.name,b.age1 as age from a,b where a.id=b.id union all
select a.id,a.name,c.age2 as age from a,c where a.id=c.id
