如何解决如何根据条件订购? SQL服务器
例如,我有一个下表:
ID NAME Company StartDate EndDate Status
--------------------------------------------------------------------------------------
50 Bob ABC 11-15-2016 02-05-2017 Former
50 Bob XYZ 05-06-2014 05-06-2015 Former
50 Bob EFG 06-10-2019 NULL Active
50 Bob LMN 07-05-2019 NULL Active
我试图按降序列出他们最近的3个工作,因此他们的“活动”工作将排在第一位,但是如果他们有2个“活动”的工作,如上面的示例,我只想拉“活动”具有最近开始日期的作业,或者如果两个“活动”作业都具有相同的开始日期,则只需随机选择其中一个,然后跳过另一个“活动”,然后继续执行其最近的先前作业。 “活动”作业将始终具有NULL EndDate值。
所以我要寻找的结果集如下:
ID NAME Company StartDate EndDate Status rn
----------------------------------------------------------------------------------------------
50 Bob LMN 07-05-2019 NULL Active 1
50 Bob ABC 11-15-2016 02-05-2017 Former 2
50 Bob XYZ 05-06-2014 05-06-2015 Former 3
我尝试了下面的代码,但是它无法检查两个活动作业的状态并正确地给他们一个行号。根据上述条件,我只希望其中一个活动作业为rn = 1,而rn = 2和rn = 3将是最后2个“前”作业:
select *,row_number() over (partition by ID,NAME order by CASE WHEN Status = 'Active' AND
EndDate is NULL THEN Status END desc,EndDate desc
) rn
from employment
解决方法
您可以使用窗口功能执行此操作。假设“ Active”和“ Former”是仅有的两个可能的状态值,则可以执行以下操作:
select *
from (
select t.*,row_number() over (partition by id,status order by startDate desc) rn
from mytable t
) t
where
(status = 'Active' and rn = 1)
or (status <> 'Active' and rn <= 2)
如果可能还有其他状态,则可以将窗口功能更改为:
row_number() over (
partition by id,case when status = 'Active' then 1 else 0 end
order by startDate desc
) rn
最后,如果您要使用startDate
来订购“有效”的建议,而要使用endDate
来订购其他的,则:
row_number() over (
partition by id,case when status = 'Active' then 1 else 0 end
order by case when status = 'Active' then startDate else endDate end desc
) rn
,
您可以使用CTE获取最新的“活动”作业,使用rn获得“以前的”作业,然后使用UNION:
;with cte1 as
(
select Id,Name,C.Company,C.StartDate,C.EndDate,C.Status,rn = 1
From employment E
Outer Apply
(
Select top 1 E2.Company,E2.StartDate,E2.EndDate,E2.Status
From employment E2
where E.Id = E2.Id and E.Name = E2.Name
and E2.Status = 'Active'
order by E2.StartDate desc
) C
group by E.Id,E.Name,C.Status
),cte2 as
(
select *,1 + row_number() over (partition by ID,NAME order by StartDate desc
) rn
from employment
where Status = 'Former'
)
select * from cte1
union
select * from cte2
where rn <= 3
order by Id asc,Name asc,StartDate desc
输出:
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。