如何在sql中重用一个子查询?
发布时间:2020-05-23 10:26:03 所属栏目:MsSql 来源:互联网
导读:我有如下的查询 select columnsfrom (select columns1 from result_set where condition_common and condition1) as subset1 join (select columns2 from result_set where conditi
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我有如下的查询 select columns
from (select columns1
from result_set
where condition_common and condition1) as subset1
join
(select columns2
from result_set
where condition_common and condition2) as subset2
on subset1.somekey = subset2.somekey
我想以某种方式重用 select columns from result_set where condition_common 我以上的查询过于简单,但上述的选择在现实中是巨大而复杂的.我不想有确保两者都同步的负担 我没有任何方法以编程方式重用它. T-SQL被排除.我只能写简单的查询.这是一个应用限制. 有没有办法在单个语句中重用同一个子查询 解决方法如果您使用SQL Server 2005,请使用 Common Table Expression(CTE):with cte as (
select columns
from result_set
where condition_common
)
select columns
from cte as subset1
join
cte as subset2
on subset1.somekey = subset2.somekey
where otherconditions (编辑:安卓应用网) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |
