[英]SQL hiearchy select query between two tables
我有2張桌子(人,部門)。
部門表如下所示:
ID (int)
Name (varchar)
ParentID (int)
人物表如下:
Id (int)
FirstName (varchar)
SureName (varchar)
DepartmentId (int)
Manager (Bool)
Asistant (Bool)
我需要創建查詢,該查詢選擇混凝土部門經理的混凝土人的所有直接下屬。 一個查詢不僅選擇了經理的直接下屬,而且還選擇了所有查詢。 每個部門都有一名經理和一名助理。 經理==假的人是直接下屬,處於子公司中的人是父母中的下屬。
我不知道如何在SQL / LINQ中創建此查詢。
我將不勝感激!
示例:部門
Id Name Parent
0 Department1 null
1 Department2 0
2 Department3 1
例:
People
ID Name Department DepartmentId Manager Asistant
1 Martin Joshua 0 1 0
2 Ondra Joshua2 0 0 0
3 Petr Joshua3 0 0 0
4 Todd Joshua3 1 1 0
5 Alex Joshua3 1 0 0
6 Iva Joshua3 1 0 0
7 Otto Joshua3 2 1 0
8 Todd Joshua3 2 0 0
例如,我需要選擇ID為0的部門中所有(不僅是直接的)經理下屬,結果如下所示:
2 Ondra Joshua2 0 0 0
3 Petr Joshua3 0 0 0
4 Todd Joshua3 1 1 0
5 Alex Joshua3 1 0 0
6 Iva Joshua3 1 0 0
7 Otto Joshua3 2 1 0
8 Todd Joshua3 2 0 0
我不確定直接下屬的SQL查詢:
SELECT * FROM dbo.PeopleView WHERE DepartmentId = 162 AND Manager = 0; -- all direct s (162)
解:
;WITH CTE AS
(
SELECT 1 as EMPLEVEL, H1.Id, H1.ParentId, H1.Name FROM DepartmentView H1 WHERE Id = 6
UNION ALL
SELECT EMPLEVEL + 1, H2.Id, H2.ParentId, H2.Name FROM DepartmentView H2
INNER JOIN CTE ON H2.ParentId = CTE.Id
)
SELECT DISTINCT P.Id, P.LastName,P.FirstName,P.DepartmentId,P.Manager,P.Assistant FROM CTE as T JOIN PeopleView as P on T.Id = P.DepartmentId;
除了第一個查詢外,就像@Andrew的評論中所述,遞歸查詢可以幫助您:
;WITH CTE
AS
(
SELECT ID,FirstName,SureName,DepartmentID,Manager,Assistant, 0 AS EMPLEVEL FROM PEOPLE A WHERE DepartmentId = 1 AND Manager = 0
UNION ALL
SELECT B.ID,B.FirstName,B.SureName,B.DepartmentID,B.Manager,B.Assistant,EMPLEVEL +1 FROM PEOPLE B
INNER JOIN DEPARTMENT D
ON B.DepartmentID = D.ID
INNER JOIN CTE
ON D.ParentID = CTE.DepartmentID
)
SELECT DISTINCT * FROM CTE
為了轉換為LINQ,您可以閱讀這篇文章:P: linq-to-sql中的通用表表達式(CTE)?
希望對您有幫助,最好的問候。
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