Question

这是针对SQL Server 2012：我的CTE中的数据子集看起来像这样：

Employee | OrderID | OrderType
---------+---------+----------
Kala     | 321111  | 953
Paul     | 321222  | 1026
Don      | 321333  | 1026
Don      | 321333  | 953
Kala     | 321444  | 953

我想要以下结果：

Employee | 953_Order_Count | 1026_Order_Count
---------+-----------------+-----------------
Kala     |        2        |    0
Don      |        1        |    1
Paul     |        0        |    1

当我跑步时，可以验证我想要的东西是否存在：

SELECT 
    Employee,
    OrderType,
    COUNT(DISTINCT OrderID) AS 'Count'
FROM
    CTE
GROUP BY 
    employee, ordertype

返回以下结果：

Employee | OrderType | Count
---------+-----------+------
Kala     | 953       | 1
Paul     | 1026      | 1
Don      | 1026      | 1
Don      | 953       | 1

关闭，但不够关闭。所以我跑：

SELECT 
    Employee,
    COUNT(DISTINCT OrderID) AS 'Total_Orders',
    COUNT(DISTINCT (CASE WHEN OrderType = 1026 THEN OrderID END)) AS '1026_Order_Count',
    COUNT(DISTINCT(CASE WHEN OrderType = 953 THEN OrderID END)) AS '953_Order_Count'
FROM
    CTE
GROUP BY 
    Employee

结果是第一个准确的“计数”，但其余的返回0。如果这不是CTE，则将使用递归语句。

感谢您的帮助！

Answer 1

只需使用条件聚合：

SELECT
    Employee,
    COUNT(CASE WHEN OrderType = 953  THEN 1 END) AS [953_Order_Count],
    COUNT(CASE WHEN OrderType = 1026 THEN 1 END) AS [1026_Order_Count]
FROM CTE
GROUP BY
    Employee;

Demo

例如，953计数在上面的工作方式是：当订单类型为953时为1，而当订单类型不是953时为NULL（隐式ELSE值）。COUNT默认情况下会忽略NULL，因此它只计算953个订单。

Answer 2

蒂姆的答案看起来不错。您还可以使用PIVOT：

; with cte (Employee, OrderID, OrderType)
as
(
    select 'Kala', 321111, 953
union select 'Paul', 321222, 1026
union select 'Don', 321333, 1026
union select 'Don', 321333, 953
union select 'Kala', 321444, 953
)
select Employee, [953] as [953_Order_Count],[1026] as [1026_Order_Count]
from 
    (
        select Employee, OrderType from cte ) as sourceData
pivot
(
    count(OrderType)
    for OrderType
    in ([953],[1026])
) as myPivot

如果要基于OrderType列中的一组可用值来创建动态列，则可以动态构建查询。有关示例，请参见@Taryn对Understanding PIVOT function in T-SQL的回答。

来自CTE的多个COUNT（DISTINCT）

2 个答案:

Demo