用类似这样一个视图来替换create view v_view2
select a.*,b.* from a inner join b on a.colume1=b.colume1 left join aa on a.colume1=aa.colume1
union all
select a.*,c.* from a inner join c on a.colume1=c.colume1 left join aa on a.colume1=aa.colume1
union all
...
...
...
(总共7个)
查询语句就可以用
select * from v_view2
select a.*,b.* from a inner join b on a.colume1=b.colume1 left join aa on a.colume1=aa.colume1
union all
select a.*,c.* from a inner join c on a.colume1=c.colume1 left join aa on a.colume1=aa.colume1
union all
...
...
...
(总共7个)
查询语句就可以用
select * from v_view2
select a.*,b.*,aa.* from a inner join b on a.colume1=b.colume1 left join aa on a.colume1=aa.colume1
union all
select a.*,c.*,aa.* from a inner join c on a.colume1=c.colume1 left join aa on a.colume1=aa.colume1
union all
...
...
...
(总共7个)
查询语句就可以用
select * from v_view2
但是我要连接的不只一个字段。我加一个字段select a.*,(select aa.colume2 from aa where aa.colume1=a.colume1) as colume2,(select aa.colume3 from aa where aa.colume1=a.colume1) as colume3 from v_view1 a也能执行,但是记录明显少了。这又是什么问题呢?怪了。
select a.* ,b.*,aa.* from a
inner join
(
select * from b
union all
select * from c
-----这里7个
)b
on a.colume1=b.colume1
left join aa
on a.colume1=aa.colume1goselect * from v_view1