Question

一个简单的问题，适用于所有SQL大师：我有以下表结构（不包括不相关的列）;

Area -- AreaID, AreaName
District -- DistrictID, DistrictName, AreaID
Office -- OfficeID, OfficeName, DistrictID
Customer -- CustomerID, OfficeID

我需要能够获得办公室中的客户数量，按区域分组，然后按Distric分组，给定AreaID作为输入参数;

DistrictID1 DistrictName1 Count_of_customers
DistrictID2 DistrictName1 Count_of_customers
...

和按AreaID（无输入参数）分组的客户数

Area1 Count_of_customers
Area2 Count_of_customers
....

Answer 1

像这样的查询应该可以解决问题

Select D.DistrictID, D.DistrictName, Count(*)
FROM District AS D
INNER JOIN Office AS O
ON D.DistrictID = O.DistrictID
INNER JOIN Customers AS C
ON O.OfficeID = C.OfficeID
WHERE D.AreaID = 1234
GROUP BY D.DistrictID, D.DistrictName

对于该地区的客户数量，您可以执行以下操作

Select A.AreaID,A.AreaName, Count(*)
FROM Area AS A
INNER JOIN District AS D
ON A.AreaID = D.AreaID
INNER JOIN Office AS O
ON D.DistrictID = O.DistrictID
INNER JOIN Customers AS C
ON O.OfficeID = C.OfficeID
GROUP BY A.AreaID,A.AreaName

SQL查询总计

1 个答案: