MSSQL - 结合两个 SELECTS，包括 JOIN 和 COUNT答案

【问题标题】：MSSQL- Combine two SELECTS, that include JOIN and COUNTMSSQL - 结合两个 SELECTS，包括 JOIN 和 COUNT
【发布时间】：2017-03-16 15:10:02
【问题描述】：

我是 Stackoverflow 的新手。希望我的问题不是愚蠢的！

我有两个 SELECTS 我必须合并。我尝试过 UNION 和另一个 JOIN，但没有成功。

SELECT 
Person.Name, Saldo1.Duration AS Holiday, Saldo2.Duraten AS Hours
FROM Person_Saldo AS Saldo1 
JOIN Person_Saldo AS Saldo2 ON Saldo1.Person_ID = Saldo2.Person_ID
JOIN Person ON Saldo1.Person_ID = Person.ID
WHERE Person.Group_ID= '1' AND Person.Active = 'true' AND Saldo1.Year = '2017' AND Saldo1.Timekonto = '4' AND Saldo2.Timekonto='52'

和第二个选择：

SELECT
Person_ID, Count([Date]) AS Amount 
FROM Booking Where Timekonto = 54 AND Booking_OK = 1 Group by Person_ID

第一个 SELECT 显示如下内容：

Name Holiday Hours A 20 50 B 12 -30

第二个是这样的：

ID Amount A 4 B 3

我的尝试：
Name Holiday Hours Amount A 20 50 4 B 12 -30 3

谢谢，希望你能帮到我。

【问题讨论】：

标签： sql-server select join count

【解决方案1】：

一种方法是将聚合查询加入主查询，如下所示：

SELECT 
    Person.Name
  , Saldo1.Duration AS Holiday
  , Saldo2.Duraten AS Hours
  , b.Amount
FROM Person_Saldo AS Saldo1 
JOIN Person_Saldo AS Saldo2 ON Saldo1.Person_ID = Saldo2.Person_ID
JOIN Person ON Saldo1.Person_ID = Person.ID
left join (
  SELECT Person_ID, Count([Date]) AS Amount 
  FROM Booking 
  Where Timekonto = 54 
    AND Booking_OK = 1 
  Group by Person_ID
  ) b on b.Person_ID = Saldo1
WHERE Person.Group_ID= '1' 
  AND Person.Active = 'true' 
  AND Saldo1.Year = '2017' 
  AND Saldo1.Timekonto = '4' 
  AND Saldo2.Timekonto='52'

如果count () 可能是null，您可能希望使用left join 而不是inner join 来表示您仍希望在结果中返回的人。

您也可以使用outer apply() 或cross apply() 来获得相同的结果。

SELECT 
    Person.Name
  , Saldo1.Duration AS Holiday
  , Saldo2.Duraten AS Hours
  , b.Amount
FROM Person_Saldo AS Saldo1 
JOIN Person_Saldo AS Saldo2 ON Saldo1.Person_ID = Saldo2.Person_ID
JOIN Person ON Saldo1.Person_ID = Person.ID
outer apply (
  SELECT Count([Date]) AS Amount 
  FROM Booking as i
  Where i.Person_Id = Saldo1.PersonId
    AND i.Timekonto = 54 
    AND i.Booking_OK = 1 
  ) as b 
WHERE Person.Group_ID= '1' 
  AND Person.Active = 'true' 
  AND Saldo1.Year = '2017' 
  AND Saldo1.Timekonto = '4' 
  AND Saldo2.Timekonto='52'

【讨论】：

谢谢，这对我帮助很大！
@mhuber 乐于助人！

【解决方案2】：

您可以使用“With”以使其更清晰。您可以在两个表之间使用左外连接。

   WITH Table2 as (
   SELECT
   Person_ID, Count([Date]) AS Amount 
   FROM Booking Where Timekonto = 54 AND Booking_OK = 1 Group by Person_ID)


Select Name, Holiday, Hours, Amount
from (SELECT 
    Person.Name, Saldo1.Duration AS Holiday, Saldo2.Duraten AS Hours
    FROM Person_Saldo AS Saldo1 
    JOIN Person_Saldo AS Saldo2 ON Saldo1.Person_ID = Saldo2.Person_ID
    JOIN Person ON Saldo1.Person_ID = Person.ID
    WHERE Person.Group_ID= '1' AND Person.Active = 'true' 
    AND Saldo1.Year = '2017' AND Saldo1.Timekonto = '4'
    AND Saldo2.Timekonto='52') Table1 LEFT OUTER JOIN
    Table2 on Table2.Person_ID=Table1.Name

【讨论】：