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Question

私のデータベースに問題があります。私は冒険作品2014を使ってそれを複製しました。

私は、BusinessEntityIDが複数回表示されているすべての結果を表示したいと思います。ユーザーが2つの部門のメンバーになっている場合、IDは2回表示されます

しかし、これは私が以下のクエリで得るものです。

SELECT Person.FirstName, 
     Person.LastName, 
     HumanResources.Department.Name AS CurrentDepartment, 
     StartDate, 
     EndDate 
FROM AdventureWorks2014.Person.Person 
JOIN HumanResources.EmployeeDepartmentHistory 
    ON HumanResources.EmployeeDepartmentHistory.BusinessEntityID = Person.BusinessEntityID 
JOIN HumanResources.Department 
    ON EmployeeDepartmentHistory.DepartmentID = HumanResources.Department.DepartmentID 
GROUP BY Person.BusinessEntityID, 
     HumanResources.Department.DepartmentID, 
     Person.FirstName, 
     Person.LastName, 
     HumanResources.Department.Name, 
     StartDate, 
     EndDate 
HAVING COUNT(Person.BusinessEntityID) > 1 
ORDER BY Person.LastName, StartDate 

私は結果（テーブル全体を）返されたのですか持っを削除します。だから私は問題がどこにあるのか/解決する方法を知っていると思う。

Answer 1

と従業員のリストに参加する必要がある、私はあなたが本当に欲しいと思うことは、例えば、EmployeeDepartmentHistoryで複数のレコードを持つ人々であります

SELECT BusinessEntityID 
FROM HumanResources.EmployeeDepartmentHistory 
GROUP BY BusinessEntityID 
HAVING COUNT(*) > 1 

私はあなたの現在のクエリにこれを統合するための最も効率的な方法はEXISTSを使用していると思う：

SELECT p.FirstName, 
     p.LastName, 
     d.Name AS CurrentDepartment, 
     edh.StartDate, 
     edh.EndDate 
FROM Person.Person AS p 
     JOIN HumanResources.EmployeeDepartmentHistory AS edh 
      ON edh.BusinessEntityID = p.BusinessEntityID 
     JOIN HumanResources.Department AS d 
      ON d.DepartmentID = edh.DepartmentID 
WHERE EXISTS 
     ( SELECT 1 
      FROM HumanResources.EmployeeDepartmentHistory AS edh2 
      WHERE edh2.BusinessEntityID = p.BusinessEntityID 
      HAVING COUNT(*) > 1 
     ) 
ORDER BY p.LastName, StartDate 

Answer 2

あなたのクエリは正常に動作すると仮定し、グループを含めないとすべての従業員を連れてきます。だから、あなたは1部門あなたは別にグループ化を行う必要があり

JOIN (SELECT P.BusinessEntityID --, COUNT(EDH.DepartmentID) for debug 
     FROM AdventureWorks2014.Person.Person P 
     JOIN HumanResources.EmployeeDepartmentHistory EDH 
     ON P.BusinessEntityID = EDH.BusinessEntityID 
     GROUP BY P.BusinessEntityID 
     HAVING COUNT(EDH.DepartmentID) > 1 
    ) as list_of_employees_with_two_or_more 
ON AdventureWorks2014.Person.Person.BusinessEntityID = 
    list_of_employees_with_two_or_more.BusinessEntityID 

Answer 3

WITH cte AS (
    SELECT Person.FirstName AS FirstName, 
      Person.LastName AS LastName, 
      Person.BusinessEntityID AS BusinessEntityID 
    FROM AdventureWorks2014.Person.Person 
    INNER JOIN HumanResources.EmployeeDepartmentHistory 
     ON HumanResources.EmployeeDepartmentHistory.BusinessEntityID = Person.BusinessEntityID 
    INNER JOIN HumanResources.Department 
     ON EmployeeDepartmentHistory.DepartmentID = HumanResources.Department.DepartmentID 
    GROUP BY Person.FirstName, 
      Person.LastName, 
      Person.BusinessEntityID 
    HAVING COUNT(*) > 1 
) 

SELECT Person.FirstName, 
     Person.LastName, 
     HumanResources.Department.Name AS CurrentDepartment, 
     StartDate, 
     EndDate 
FROM AdventureWorks2014.Person.Person 
INNER JOIN HumanResources.EmployeeDepartmentHistory 
    ON HumanResources.EmployeeDepartmentHistory.BusinessEntityID = Person.BusinessEntityID 
INNER JOIN HumanResources.Department 
    ON EmployeeDepartmentHistory.DepartmentID = HumanResources.Department.DepartmentID 
INNER JOIN cte t 
    ON Person.FirstName = t.FirstName AND 
     Person.LastName = t.LastName AND 
     Person.BusinessEntityID = t.BusinessEntityID