使用T-SQL操作面试SQL Server开发人员

     来源：builder.com    作者：builder.com

预备考试脚本

在开始考试之前，我需要一个模式和一些数据来运行所要考核的查询，列表A创建了所需的这些数据：

列表A：

IF OBJECT_ID('Sales') > 0
       DROP TABLE Sales
 GO
 IF OBJECT_ID('Customers') > 0
       DROP TABLE Customers
 GO
 IF OBJECT_ID('Products') > 0
       DROP TABLE Products
 GO
 CREATE TABLE Customers
 (
 CustomerID INT IDENTITY PRIMARY KEY,
 FirstName VARCHAR(50),
 LastName VARCHAR(50),
 City VARCHAR(50),
 State CHAR(2),
 Zip VARCHAR(10)
 )
 GO
 CREATE TABLE Products
 (ProductID TINYINT IDENTITY PRIMARY KEY,
ProductName VARCHAR(20),RecommendedPrice 
MONEY,Category VARCHAR(10)
 )GO CREATE TABLE Sales(SaleID INT IDENTITY 
PRIMARY KEY,ProductID TINYINT NOT NULL 
REFERENCES Products(ProductID),CustomerID INT 
NOT NULL REFERENCES Customers(CustomerID),SalePrice 
MONEY NOT NULL,SaleDate SMALLDATETIME NOT NULL)GO
 INSERT INTO Products(ProductName, RecommendedPrice, Category)
VALUES('DVD',105,'LivingRoom')INSERT INTO 
Products(ProductName, RecommendedPrice, Category) 
VALUES('Microwave',98,'Kitchen')INSERT 
INTO Products(ProductName, RecommendedPrice, 
Category)VALUES('Monitor',200,'Office')INSERT 
INTO Products(ProductName, RecommendedPrice, Category)
VALUES('Speakers',85,'Office')INSERT INTO 
Products(ProductName, RecommendedPrice, Category) 
VALUES('Refrigerator',900,'Kitchen')INSERT INTO 
Products(ProductName, RecommendedPrice, Category)
VALUES('VCR',165,'LivingRoom')
 INSERT INTO Products(ProductName, RecommendedPrice, Category)
 VALUES('CoffeePot',35,'Kitchen')GO
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('John','Miller','Asbury','NY','23433') INSERT INTO 
Customers(FirstName, LastName, City, State, Zip) 
VALUES('Fred','Hammill','Basham','AK','85675')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Stan','Mellish','Callahan','WY','38556')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Adrian','Caparzo','Denver','CO','12377')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Mike','Horvath','Easton','IN','47130')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Irwin','Wade','Frankfurt','KY','45902')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('George','Marshall','Gallipoli','ND','34908')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Frank','Costello','Honolulu','HI','23905')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Billy','Costigan','Immice','SC','75389')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Shelly','Sipes','Lights','AZ','35263')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Chirsty','Melton','Spade','CA','97505')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Amanda','Owens','Flask','CN','50386')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Brittany','Smits','Bourbon','KY','24207')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Kristy','Bryant','Tarp','FL','58960')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Kelly','Street','TableTop','ID','57732')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Tricia','Hill','Camera','ME','46738')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Holly','Raines','Compact','MS','35735')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Natalie','Woods','Woods','IN','87219')
 INSERT INTO Customers(FirstName, LastName, City, State, Zip) 
VALUES('Wendy','Hilton','Action','KY','47093')
 GO
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(1,1,130,'2/6/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(2,2,97,'1/7/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,3,200,'8/8/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(4,4,80,'4/9/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(5,5,899,'10/10/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(6,6,150,'10/11/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,7,209,'12/12/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(4,8,90,'5/13/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(6,9,130,'6/14/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(2,14,85,'6/19/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,15,240,'9/20/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(1,16,99,'7/21/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(1,17,87,'3/22/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(2,18,99,'1/23/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(6,19,150,'3/24/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(5,5,900,'3/10/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(4,6,86,'8/11/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(2,7,88,'8/12/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,8,198,'12/13/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(1,9,150,'5/14/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(6,14,99,'7/19/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(6,15,104,'9/20/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,16,270,'2/21/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(4,17,90,'7/22/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(1,1,130,'3/6/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(2,2,102,'4/7/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(1,3,114,'11/8/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(5,4,1000,'5/9/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(5,5,1100,'10/10/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,6,285,'6/11/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(2,7,87,'10/12/2005')
 INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) 
VALUES(3,8,300,'7/13/2005')
 GO

一旦我载入了这些数据，我就可以开始测试了（提示：我会让应聘者将他们编写的SELECT/UPDATE/INSERT/DELETE 语句存储在一个文本文件中，这样我以后可以随时阅览）。

测试

测试项目#1：返回在2005年10月售出的所有产品的名称、价格和客户姓名，答案见列表B：

SELECT
c.FirstName, c.LastName, p.ProductName, s.SalePrice
FROM
Sales s
INNER JOIN Customers c ON s.CustomerID = c.CustomerID
INNER JOIN Products p ON s.ProductID = p.ProductID
WHERE
s.SaleDate >= '10/1/2005' AND
s.SaleDate < '11/1/2005'

测试项目#2：返回没有购买产品并且位于客户表格上的人的姓名及其客户ID，答案参见列表C:

SELECT
c.CustomerID, c.FirstName, c.LastName
FROM
Sales s
RIGHT OUTER JOIN Customers c ON s.CustomerID = c.CustomerID
WHERE
s.CustomerID IS NULL

测试项目#3：返回客户姓名、销售价格、建议售价、建议售价和实际价格的差额，该差额必需是正数，答案见列表D：

SELECT
c.FirstName, c.LastName, s.SalePrice, p.RecommendedPrice, 
ABS(s.SalePrice - p.RecommendedPrice)
AS AbsoluteSalePriceDifference
FROM
Sales s
INNER JOIN Customers c ON s.CustomerID = c.CustomerID
INNER JOIN Products p ON s.ProductID = p.ProductID

测试项目#4：根据产品类别计算平均价格，答案见列表E：

SELECT
p.Category, AVG(s.SalePrice) AS AverageSalePrice
FROM
Sales s
INNER JOIN Products p ON s.ProductID = p.ProductID
GROUP BY p.Category

测试项目#5：将以下的客户和销售信息加入到数据库中：

FirstName: Chris

LastName: Kringle

City: Henryville

State: IN

Zip: 47126

ProductID: 3

SalePrice: 205

SaleDate: 12/31/2005

答案见列表F：

INSERT INTO Customers(FirstName, LastName, City, State, Zip)
VALUES('Chris', 'Kringle', 'Henryville', 'IN', '47126')
INSERT INTO Sales(CustomerID, ProductID, SalePrice, SaleDate)
VALUES(SCOPE_IDENTITY(), 3, 205, '12/31/2005')

测试项目#6：从数据库中删除来自缅因洲(‘ME’)的客户，答案见列表G：

DELETE s
FROM
Sales s
JOIN Customers c ON s.CustomerID = c.CustomerID
WHERE
c.State = 'ME'
DELETE c
FROM  
Customers c
WHERE
c.State = 'ME'

测试项目#7：返回客户购买了两个或多个产品的平均售价和产品类别，答案见列表H：

SELECT
p.Category, AVG(s.SalePrice)
FROM
Sales s 
INNER JOIN
(
SELECT s.CustomerID
FROM  
Sales s
GROUP BY s.CustomerID
HAVING COUNT(CustomerID) >= 2
) x ON s.CustomerID = x.CustomerID
INNER JOIN Products p ON s.ProductID = p.ProductID
GROUP BY p.Category

测试项目#8：将销售在2005年6月10日到6月20日之间的产品的销售价格升级为建议售价，答案见列表I：

UPDATE s
SET      SalePrice = p.RecommendedPrice
FROM
Sales s
INNER JOIN Products p ON s.ProductID = s.ProductID
WHERE
SaleDate >= '6/10/2005' AND 
SaleDate < '6/21/2005'

测试项目#9：根据产品种类计算建议售价超过实际售价10元及以上的销售数量，答案见列表J：

SELECT
p.Category, COUNT(*) AS NumberOfSales
FROM
Sales s
INNER JOIN Products p ON s.ProductID = p.ProductID
GROUP BY p.Category
HAVING      
AVG(p.RecommendedPrice) >= AVG(s.SalePrice)+10

测试项目#10：不使用叠代构建，返回所由销售产品的销售日期，并按照该日期升序排列，答案见列表K：

SELECT
s.SaleDate, 
s.SalePrice,
(
SELECT 
SUM(SalePrice)
FROM
Sales s2
WHERE
s2.SaleDate <= s.SaleDate
) AS RunningTotal
FROM
Sales s
ORDER BY 
s.SaleDate ASC

评分

我曾经使用类似的考题去考察很多应聘SQL Server数据库开发职位的人，但是迄今为止，只有2个人可以正确地回答出所有的问题。

平均分大约为50－60％，如果应聘者的表现高于这个平均分，那么我就认为他或她是一位优秀的TSQL程序员，如果应聘者获得了90％以上的得分，那么他或她就是一位非常优异的程序员。