第一次提问者 -- 我在 SqlServer 2012 中结合案例逻辑和窗口时遇到一些问题。我需要展平如下所示的数据结构,因此之后我将针对这些结果运行 MAX 语句。我使用 case/when 逻辑为每个 xID 指定一个“所有者”。我的挑战是我一直得到错误的结果,而且我无法确定我做错了什么。
这是 case/when 逻辑和表结构。对于“Owner”列,我需要评估三个条件,并尝试使用 FIRST_VALUE() 来选择 case 语句的输出。 case 语句中的逻辑工作正常,但是当我尝试使用窗口函数将值应用于每个 xID 时,它返回错误的值。
FIRST_VALUE(case
when [partnerType] = 'Giver' and [partnerAgree] = 'True' then [partnerGroup]
when [partnerType] = 'Impacted' and [partnerAgree] = 'True' then [partnerGroup]
when [Stakeholder No#] = 1 and [partnerAgree] <> 'True' then [partnerGroup]
else Null end) over (partition by [xID] order by [yID])
as 'Owner'
Desired Results --------------------------
|xID|yID| Owner |partnerType| partnergrp|partnerAgree
|100| 1| grp_Banana|Taker |grp_Apple |TRUE
|100| 2| grp_Banana|Giver |grp_Banana |TRUE
|100| 3| grp_Banana|Taker |grp_Banana |FALSE
|101| 1| grp_Carrot|Taker |grp_Carrot |TRUE
|101| 2| grp_Carrot|Giver |grp_Danish |FALSE
|101| 3| grp_Carrot|Taker |grp_Banana |TRUE
|101| 4| grp_Carrot|Taker |grp_Danish |FALSE
Results I'm getting --------------------------
|xID|yID| Owner |partnerType| partnergrp|partnerAgree
|100| 1| grp_Apple |Taker |grp_Apple |TRUE
|100| 2| grp_Apple |Giver |grp_Banana |TRUE
|100| 3| grp_Apple |Taker |grp_Banana |FALSE
|101| 1| grp_Carrot|Taker |grp_Carrot |TRUE
|101| 2| grp_Carrot|Giver |grp_Danish |FALSE
|101| 3| grp_Carrot|Taker |grp_Banana |TRUE
|101| 4| grp_Carrot|Taker |grp_Danish |FALSE
第一个表显示了我所期望的结果,但代码生成了第二个表中的值。示例:对于 xID=100,我希望所有者是 grp_Banana,但我的代码返回 grp_Apple。对于 xID=101 我得到了正确的答案,但原因错误。窗口函数似乎采用任何结果集的第一个 yID。
谢谢,非常感谢任何帮助。另外,我愿意不使用窗口函数,这似乎是正确的方向。
最佳答案
除非您的数据库支持ignore null
s 参数,否则这很棘手。您可以使用两个窗口函数来完成此操作:
max(case when yid = yid_special then partnerGroup end) over (partition by xid) as Owner
from (select . . . ,
min(case when partnerType = 'Giver' and [partnerAgree] = 'True' then yid
when partnerType = 'Impacted' and [partnerAgree] = 'True' then yid
when [Stakeholder No#] = 1 and [partnerAgree] <> 'True' then yid
end) over (partition by xid) as yid_special
您也可以使用 first_value()
编写此代码:
first_value(partnerGroup) over
(partition by xid
order by (case when partnerType = 'Giver' and [partnerAgree] = 'True' then yid
when partnerType = 'Impacted' and [partnerAgree] = 'True' then yid
when [Stakeholder No#] = 1 and [partnerAgree] <> 'True' then yid
else 999999
end)
) as owner
关于SQL - 使用窗口和 case 语句展平表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55344650/