Question

我对SQL Server查询有疑问。

表格可以描述如下：

供应商（SID, sName, status, sCity），PK = SID
零件（PID, pName, color, weight, pCity），PK = PID
项目（JID, jName, city），PK = JID
SPJ （SID, PID, JID, quantity），PK =（SID，PID，JID），FK = SID，PID，JID

我正在尝试将同一部件的供应商的供应商编号和名称提供给至少两个项目，这是我对该任务的查询：

SELECT 
    s1.SID, s1.sName, COUNT(*)
FROM 
    Suppliers s1, Parts p, SPJ s2
WHERE 
    s1.SID = s2.SID 
    AND p.PID = s2.PID 
GROUP BY 
    s1.SID, s1.sName
HAVING 
    COUNT(*)>1
ORDER BY 
    s1.SID, s1.sName

请帮我更正此查询。提前谢谢

Answer 1

这正是你所要求的：

SELECT
   S.SupplierID,
   S.sName
FROM
   dbo.Suppliers S
WHERE
   EXISTS (
      SELECT *
      FROM dbo.SPJ SPJ
      WHERE S.SupplierID = SPJ.SupplierID
      GROUP BY SPJ.PartID
      HAVING Count(*) >= 2
   );

Please see my SQLFiddle在真实数据集上试用它。请注意，还有一个查询显示参与使供应商符合资格的所有各行（请参阅Qualifies列）。以下是安装脚本的预览：

CREATE TABLE dbo.Suppliers (
   SupplierID smallint identity(1,1) NOT NULL CONSTRAINT PK_Suppliers PRIMARY KEY CLUSTERED,
   sName varchar(40) NOT NULL CONSTRAINT UQ_Suppliers_sName UNIQUE
);

CREATE TABLE dbo.Parts (
   PartID int identity(1,1) NOT NULL CONSTRAINT PK_Parts PRIMARY KEY CLUSTERED,
   pName varchar(100) NOT NULL CONSTRAINT UQ_Parts_pName UNIQUE
);

CREATE TABLE dbo.Projects (
   ProjectID int identity(1,1) NOT NULL CONSTRAINT PK_Projects PRIMARY KEY CLUSTERED,
   jName varchar(50) NOT NULL CONSTRAINT UQ_Projects_jName UNIQUE
);

CREATE TABLE dbo.SPJ (
   SupplierID smallint NOT NULL CONSTRAINT FK_SPJ_Suppliers FOREIGN KEY REFERENCES dbo.Suppliers (SupplierID),
   PartID int NOT NULL CONSTRAINT FK_SPJ_Parts FOREIGN KEY REFERENCES dbo.Parts (PartID),
   ProjectID int NOT NULL CONSTRAINT FK_SPJ_Projects FOREIGN KEY REFERENCES dbo.Projects (ProjectID),
   CONSTRAINT PK_SPJ PRIMARY KEY CLUSTERED (SupplierID, PartID, ProjectID)
);

INSERT dbo.Suppliers
VALUES
   ('Joe'' Specialty Goods'),
   ('Major Supplier'),
   ('Small Supplier'),
   ('Tamandua Manufacturing, Ltd.'),
   ('Things ''n'' Stuff'),
   ('Stuff ''n'' Things');

INSERT dbo.Parts
VALUES
   ('Watchamacallit'),
   ('Thingamajiggy'),
   ('Thingamabob'),
   ('Doohickey'),
   ('Whatsisname'),
   ('Thingy'),
   ('Gizmo'),
   ('Gadget'),
   ('Widget'),
   ('Titanium Widget'),
   ('Electronic Thingamabob'),
   ('One-Product Patrick');

INSERT dbo.Projects
VALUES
   ('Video Game Manufacturing'),
   ('Autodoc Research'),
   ('Consumer Electronics Expansion'),
   ('Space Shuttle'),
   ('Tablet Project Cobalt');

INSERT dbo.SPJ
VALUES
   (1, 2, 1),
   (1, 3, 1),
   (1, 7, 1),
   (1, 11, 1),
   (2, 1, 1),
   (2, 1, 2),
   (2, 1, 3),
   (2, 1, 4),
   (2, 2, 1),
   (2, 2, 2),
   (2, 2, 3),
   (2, 2, 4),
   (2, 2, 5),
   (2, 10, 1),
   (2, 10, 2),
   (2, 10, 3),
   (2, 10, 4),
   (2, 10, 5),
   (3, 5, 4),
   (4, 4, 2),
   (4, 4, 3),
   (5, 9, 1),
   (5, 8, 2),
   (5, 7, 3),
   (5, 6, 4),
   (5, 5, 5),
   (6, 1, 1),
   (6, 2, 1),
   (6, 3, 1),
   (6, 4, 1),
   (6, 5, 1),
   (6, 6, 1),
   (6, 7, 1),
   (6, 8, 1),
   (6, 9, 1),
   (6, 10, 1),
   (6, 11, 1);

Answer 2

SELECT SID, PID, COUNT(JID)
FROM SPJ
GROUP BY SID, PID
HAVING COUNT(JID) > 1

Answer 3

你也可以这样做：

SELECT DISTINCT
a.SupplierID,
b.sName
FROM
(
  SELECT
   SupplierID,
   PartID,
   NumProjects = count(DISTINCT ProjectID)
  FROM SPJ
  GROUP BY
   SupplierID, PartID
  HAVING 
   count(DISTINCT ProjectID) >= 2 
) a
INNER JOIN Suppliers b ON a.SupplierID = b.SupplierID

Answer 4

SELECT Supplier.SID,Supplier.sName
FROM SPJ inner join Supplier on SPJ.SID = Supplier.SID
inner join Parts on SPJ.PID = Parts.PID
GROUP BY Supplier.SID,Supplier.sName
HAVING COUNT(JID) > 1

从三列多对多表中显示在至少两个col 3中具有相同col 2的col 1的名称

4 个答案: