MSSQL表查詢問題

Question

有人可以告訴我在兩個表之間使用MSSQL來獲取正確數據結果的方法，如下所示

**Person_Table**          **Departemnt_Table**
===========                 ================
person_id                   depatment_id
age                         department name 
gender                         
department_id

而且，我想得到以下列的結果：

Department Names, 
Number under 20 aged Males in each department, 
number of under 20 aged Females in each department, 
total number of Males in each department, 
total number of Females in each department and, 
Total number of Persons in each department

示例結果應如下所示

DepartmentName|(Under20)Male|(Under20)Female|Total(M)| Total(F)| Grand Total
Department1   |    1        |  3            |  1     |  3      |   4  
Department2   |    3        |  1            |  15    |  1      |   16
Department3   |    0        |  0            |  0     |  0      |   0

Answer 1

您需要使用帶有聚合函數的GROUP BY子句。

SELECT DT.DepartmentName,
        SUM(CASE WHEN PT.age < 20 AND PT.gender='MALE' THEN 1 ELSE 0 END) As [(Under20)Male]
       ,SUM(CASE WHEN PT.age < 20 AND PT.gender='FEMALE' THEN 1 ELSE 0 END) As [(Under20)FeMale],
       ,SUM(CASE WHEN PT.gender='MALE' THEN 1 ELSE 0 END) As [Total(M)]
       ,SUM(CASE WHEN PT.gender='FEMALE' THEN 1 ELSE 0 END) As [Total(F)]
       ,COUNT(*) As [Grand Total]   
FROM Departemnt_Table DT
INNER JOIN Person_Table PT ON DT.depatment_id = PT.depatment_id
GROUP BY DT.DepartmentName

Answer 2

DECLARE @Person TABLE(person_id int null,
age  int null,
gender   varchar(10) null,
department_id INT null)

DECLARE @Department TABLE(
department_id INT, DepartmentName Varchar(200))

INSERT INTO @Department VALUES (1,'A')
INSERT INTO @Department VALUES (2,'B')
INSERT INTO @Department VALUES (3,'C')
INSERT INTO @Department VALUES (4,'D')

INSERT INTO @Person VALUES (1,19,'M',1)
INSERT INTO @Person VALUES (2,12,'F',1)
INSERT INTO @Person VALUES (3,30,'M',1)
INSERT INTO @Person VALUES (4,40,'F',1)

INSERT INTO @Person VALUES (5,20,'M',2)
INSERT INTO @Person VALUES (6,12,'F',2)
INSERT INTO @Person VALUES (7,30,'M',2)
INSERT INTO @Person VALUES (8,40,'F',2)

INSERT INTO @Person VALUES (9,20,'M',3)
INSERT INTO @Person VALUES (10,12,'F',3)
INSERT INTO @Person VALUES (11,30,'M',3)
INSERT INTO @Person VALUES (12,40,'F',3)

INSERT INTO @Person VALUES (13,20,'M', 4)
INSERT INTO @Person VALUES (14,12,'F',4)
INSERT INTO @Person VALUES (15,30,'M',4)
INSERT INTO @Person VALUES (16,17,'F',4)


Select  D.DepartmentName ,
SUM([(Under20)Male]) [(Under20)Male],
SUM([(Under20)Female])[(Under20)Female],
SUM([Total(M)]) [Total(M)],
SUM([ Total(F)]) [ Total(F)],
SUM([Grand Total]) [Grand Total]
FROM

(

Select  department_id,COUNT(*) as  [(Under20)Male],0  [(Under20)Female],0 [Total(M)],0 [ Total(F)],0 [Grand Total] From @Person  WHERE age<20 and gender='M' group by department_id
Union all
Select  department_id,0 as  [(Under20)Male],COUNT(*)  [(Under20)Female],0 [Total(M)],0 [ Total(F)],0 [Grand Total] From @Person  WHERE age<20 and gender='F' group by department_id
Union all
Select  department_id,0 as  [(Under20)Male],0  [(Under20)Female],COUNT(*) [Total(M)],0 [ Total(F)],0 [Grand Total] From @Person  WHERE gender='M' group by department_id
Union all
Select  department_id,0 as  [(Under20)Male],0  [(Under20)Female],0 [Total(M)],COUNT(*) [ Total(F)],0 [Grand Total] From @Person  WHERE  gender='F' group by department_id
union all
Select  department_id,0 as  [(Under20)Male],0  [(Under20)Female],0 [Total(M)],0 [ Total(F)],COUNT(*) [Grand Total] From @Person  group by department_id
)A

INNER JOIN
 @Department D

ON A.department_id=D.department_id
GROUP BY D.DepartmentName