Question

;with cte1 as
(  select  id,
row_number() over (partition by pk,pp,sn order by id asc)
as rn
from mqms_production
) select * into #M from cte1 where rn=1

通过上面的描述，我获得了rn = 1的所有行，但我还想将给定分区pk，pp，sn的所有行复制到另一个表中。

是否可以在不必再次编写cte块的情况下执行此操作（由id DESC按pk，pp，sn顺序划分）

谢谢！

Answer 1

您可以使用反向排序顺序添加另一个基于窗口函数的表达式，并在它们两者上获得顶行

with cte1 as (
    select  id,
        row_number() over (partition by pk,pp,sn order by id asc) as rn1,
        row_number() over (partition by pk,pp,sn order by id desc) as rn2
    from mqms_production
)
select * from cte1 
where rn1 = 1 or rn2 = 1;

单个cte代码块的最大和最小行数

1 个答案: