52563.htm

一本很基础的SQL讲解

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        <td height="24" align="center" valign="bottom" class="d_font3">用T-SQL操作面试SQL Server开发人员</td>
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        <td class="d_font4"><P><STRONG>预备考试脚本</STRONG></P>
<P>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：</P>
<P><STRONG>列表A：</STRONG></P>
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<TD class=code bgColor=#e6e6e6><PRE>IF OBJECT_ID('Sales') &gt; 0 <BR>DROP TABLE Sales <BR>GO <BR>IF OBJECT_ID('Customers') &gt; 0 <BR>DROP TABLE Customers <BR>GO <BR>IF OBJECT_ID('Products') &gt; 0 <BR>DROP TABLE Products <BR>GO <BR>CREATE TABLE Customers <BR>( <BR>CustomerID INT IDENTITY PRIMARY KEY, <BR>FirstName VARCHAR(50), <BR>LastName VARCHAR(50), <BR>City VARCHAR(50), <BR>State CHAR(2), <BR>Zip VARCHAR(10) <BR>) <BR>GO <BR>CREATE TABLE Products <BR>(ProductID TINYINT IDENTITY PRIMARY KEY, <BR>ProductName VARCHAR(20),RecommendedPrice <BR>MONEY,Category VARCHAR(10) <BR>)GO CREATE TABLE Sales(SaleID INT IDENTITY <BR>PRIMARY KEY,ProductID TINYINT NOT NULL <BR>REFERENCES Products(ProductID),CustomerID INT <BR>NOT NULL REFERENCES Customers(CustomerID),SalePrice <BR>MONEY NOT NULL,SaleDate SMALLDATETIME NOT NULL)GO <BR>INSERT INTO Products(ProductName, RecommendedPrice, Category) <BR>VALUES('DVD',105,'LivingRoom')INSERT INTO <BR>Products(ProductName, RecommendedPrice, Category) <BR>VALUES('Microwave',98,'Kitchen')INSERT <BR>INTO Products(ProductName, RecommendedPrice, <BR>Category)VALUES('Monitor',200,'Office')INSERT <BR>INTO Products(ProductName, RecommendedPrice, Category) <BR>VALUES('Speakers',85,'Office')INSERT INTO <BR>Products(ProductName, RecommendedPrice, Category) <BR>VALUES('Refrigerator',900,'Kitchen')INSERT INTO <BR>Products(ProductName, RecommendedPrice, Category) <BR>VALUES('VCR',165,'LivingRoom') <BR>INSERT INTO Products(ProductName, RecommendedPrice, Category) <BR>VALUES('CoffeePot',35,'Kitchen')GO <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('John','Miller','Asbury','NY','23433') INSERT INTO <BR>Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Fred','Hammill','Basham','AK','85675') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Stan','Mellish','Callahan','WY','38556') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Adrian','Caparzo','Denver','CO','12377') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Mike','Horvath','Easton','IN','47130') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Irwin','Wade','Frankfurt','KY','45902') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('George','Marshall','Gallipoli','ND','34908') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Frank','Costello','Honolulu','HI','23905') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Billy','Costigan','Immice','SC','75389') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Shelly','Sipes','Lights','AZ','35263') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Chirsty','Melton','Spade','CA','97505') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Amanda','Owens','Flask','CN','50386') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Brittany','Smits','Bourbon','KY','24207') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Kristy','Bryant','Tarp','FL','58960') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Kelly','Street','TableTop','ID','57732') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Tricia','Hill','Camera','ME','46738') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Holly','Raines','Compact','MS','35735') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Natalie','Woods','Woods','IN','87219') <BR>INSERT INTO Customers(FirstName, LastName, City, State, Zip) <BR>VALUES('Wendy','Hilton','Action','KY','47093') <BR>GO <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(1,1,130,'2/6/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(2,2,97,'1/7/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,3,200,'8/8/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(4,4,80,'4/9/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(5,5,899,'10/10/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(6,6,150,'10/11/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,7,209,'12/12/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(4,8,90,'5/13/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(6,9,130,'6/14/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(2,14,85,'6/19/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,15,240,'9/20/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(1,16,99,'7/21/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(1,17,87,'3/22/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(2,18,99,'1/23/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(6,19,150,'3/24/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(5,5,900,'3/10/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(4,6,86,'8/11/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(2,7,88,'8/12/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,8,198,'12/13/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(1,9,150,'5/14/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(6,14,99,'7/19/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(6,15,104,'9/20/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,16,270,'2/21/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(4,17,90,'7/22/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(1,1,130,'3/6/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(2,2,102,'4/7/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(1,3,114,'11/8/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(5,4,1000,'5/9/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(5,5,1100,'10/10/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,6,285,'6/11/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(2,7,87,'10/12/2005') <BR>INSERT INTO Sales(ProductID, CustomerID, SalePrice, SaleDate) <BR>VALUES(3,8,300,'7/13/2005') <BR>GO</PRE></TD></TR></TBODY></TABLE></P>
<P>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)。</P>
<P>#p#</P>
<P><STRONG>测试</STRONG></P>
<P><STRONG>测试项目#1：</STRONG>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：</P>
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<TD class=code bgColor=#e6e6e6><PRE>SELECT <BR>c.FirstName, c.LastName, p.ProductName, s.SalePrice <BR>FROM <BR>Sales s <BR>INNER JOIN Customers c ON s.CustomerID = c.CustomerID <BR>INNER JOIN Products p ON s.ProductID = p.ProductID <BR>WHERE <BR>s.SaleDate &gt;= '10/1/2005' AND <BR>s.SaleDate &lt; '11/1/2005'</PRE></TD></TR></TBODY></TABLE></P>
<P><STRONG>测试项目#2：</STRONG>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：</P>
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<TD class=code bgColor=#e6e6e6><PRE>SELECT <BR>c.CustomerID, c.FirstName, c.LastName <BR>FROM <BR>Sales s <BR>RIGHT OUTER JOIN Customers c ON s.CustomerID = c.CustomerID <BR>WHERE <BR>s.CustomerID IS NULL</PRE></TD></TR></TBODY></TABLE></P>
<P><STRONG>测试项目#3：</STRONG>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：</P>
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<TD class=code bgColor=#e6e6e6><PRE>SELECT <BR>c.FirstName, c.LastName, s.SalePrice, p.RecommendedPrice, <BR>ABS(s.SalePrice - p.RecommendedPrice) <BR>AS AbsoluteSalePriceDifference <BR>FROM <BR>Sales s <BR>INNER JOIN Customers c ON s.CustomerID = c.CustomerID <BR>INNER JOIN Products p ON s.ProductID = p.ProductID</PRE></TD></TR></TBODY></TABLE></P>
<P><STRONG>测试项目#4：</STRONG>根据产品类别计算平均价格，答案见列表E：</P>
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<TD class=code bgColor=#e6e6e6><PRE>SELECT <BR>p.Category, AVG(s.SalePrice) AS AverageSalePrice <BR>FROM <BR>Sales s <BR>INNER JOIN Products p ON s.ProductID = p.ProductID <BR>GROUP BY p.Category</PRE></TD></TR></TBODY></TABLE></P>
<P><STRONG>测试项目#5：</STRONG>将以下的客户和销售信息加入到数据库中：</P>
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