Sql 无嵌套选择计数：这可能吗？

数据库：

Department  Position             Points
    A        Manager               50
    A        Supervisor            10
    A        Supervisor            10
    A        Staff                 2
    A        Staff                 2
    B        Manager               40
    B        SuperVisor            8
    B        Staff                 2
    B        Staff                 2
    B        Staff                 2

所需的查询结果：

Dept  Manager Count  Supervisor Count  Staff Count    Staff Total Pts   

A        1                  2              2                 4
B        1                  1              3                 4

如果不使用嵌套的select with count，是否可以得到所需的查询结果

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我们有一个与此类似的存储过程，使用嵌套计数，我们希望使其更简单，执行得更好/更快

使用

条件聚合

仅对特定数据进行计数

Select Department,
       count(case when Position = 'Manager' then 1 END) as Manager,
       count(case when Position = 'Supervisor' then 1 END) as Supervisor,
       count(case when Position = 'Staff' then 1 END) as Staff
From yourtable
Group by Department

如果您使用的是

Sql Server

，请使用此选项

SELECT Department,
       Manager,
       Supervisor,
       Staff
FROM   Yourtable
       PIVOT (Count(Position)
             FOR Position IN (Manager,Supervisor,Staff))pv 

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使用条件求和：

SELECT Department,
       SUM(CASE WHEN Position = 'Manager' THEN 1 END) as Manager,
       SUM(CASE WHEN Position = 'Supervisor' THEN 1 END) as Supervisor,
       SUM(CASE WHEN Position = 'Staff' THEN 1 END) as Staff
FROM yourtable
GROUP BY Department

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或者，您可以使用轴操作符：

select Detartment, Manager, Supervisor, Staff
from yourtable
pivot (count(Position) for Position in (Manager, Supervisor, Staff)) Result

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此外，您还可以使用PIVOT query进行此操作，谢谢。我补充了一个问题，谢谢。我补充了一个问题