之前我们介绍过：SQL Server数据库中FOR XML AUTO的使用详解，本文我们介绍一些稍微复杂的应用，首先我们先看下面的代码：
CREATE TABLE Person( ID INT IDENTITY(1,1) NOT NULL, Name NVARCHAR(20) NOT NULL DEFAULT(''), Age INT DEFAULT(0) NOT NULL, Sex BIT DEFAULT(0) NOT NULL ) --DROP TABLE [Order] CREATE TABLE [Order]( ID INT IDENTITY(1,1) PRIMARY KEY, PersonID INT DEFAULT(0) NOT NULL, TotalPrice DECIMAL DEFAULT(0) NOT NULL ) CREATE TABLE Product( ID INT IDENTITY(1,1) PRIMARY KEY, Price DECIMAL(8,2) DEFAULT(0.00) NOT NULL, Img NVARCHAR(50) DEFAULT('') NOT NULL ) CREATE TABLE OrderDetail( ID INT IDENTITY(1,1) PRIMARY KEY, OrderID INT DEFAULT(0) NOT NULL, ProductID INT DEFAULT(0) NOT NULL, Price DECIMAL(8,2) DEFAULT(0.00) NOT NULL ) INSERT INTO Person(Name,Age,Sex) SELECT '张三',28,1 UNION ALL SELECT '李四',28,1 UNION ALL SELECT '王五',28,1 INSERT INTO [Order](PersonID,TotalPrice) SELECT 1,100.0 UNION ALL SELECT 1,111.0 UNION ALL SELECT 2,112.0 UNION ALL SELECT 3,98.0 UNION ALL SELECT 3,150.49 UNION ALL SELECT 3,58 INSERT INTO Product(Price,Img) SELECT 101.0,'1.png' UNION ALL SELECT 102.0,'2.png' UNION ALL SELECT 103.0,'3.png' UNION ALL SELECT 104.0,'4.png' UNION ALL SELECT 105.0,'5.png' INSERT INTO OrderDetail(OrderID,ProductID,Price) SELECT TOP 3 3,ID,Price FROM Product SELECT * FROM Person SELECT * FROM [Order] SELECT * FROM Product SELECT * FROM OrderDetail Person ID Name Age Sex ----------- -------------------- ----------- ----- 1 张三 28 1 2 李四 28 1 3 王五 28 1 (3 行受影响) [Order] ID PersonID TotalPrice ----------- ----------- --------------------------------------- 1 1 100 2 1 111 3 2 112 4 3 98 5 3 150 6 3 58 (6 行受影响) Product ID Price Img ----------- --------------------------------------- -------------------------------------------------- 1 101.00 1.png 2 102.00 2.png 3 103.00 3.png 4 104.00 4.png 5 105.00 5.png (5 行受影响) OrderDetail ID OrderID ProductID Price ----------- ----------- ----------- --------------------------------------- 1 1 1 101.00 2 1 2 102.00 3 1 3 103.00 4 1 4 104.00 5 1 5 105.00 6 2 1 101.00 7 2 2 102.00 8 2 3 103.00 9 3 1 101.00 10 3 2 102.00 11 3 3 103.00 (11 行受影响)
理下其中的关系：
会员表Person与订单表Order为一对多关系,其中Order.PersonID = Person.ID
订单表与订单详情表为一对多关系,其中OrderDetail.OrderID = Order.ID
产品表与订单详情表为一对多关系,其中OrderDetail.ProductID = Product.ID
如下图1
图1
可以开始了:
先来看有那些订单,分别为谁的订单,以及订单详情,SQL脚本及查询结果如下：
1: SELECT 2: [Order].ID, 3: [Order].PersonID, 4: OrderDetail.OrderID, 5: OrderDetail.ProductID, 6: OrderDetail.Price 7: FROM [Order] 8: INNER JOIN OrderDetail ON [Order].ID = OrderDetail.OrderID 9: FOR XML AUTO,ROOT('Record')
查询结果如下：
1: <Record> 2: <Order ID="1" PersonID="1"> 3: <OrderDetail OrderID="1" ProductID="1" Price="101.00" /> 4: <OrderDetail OrderID="1" ProductID="2" Price="102.00" /> 5: <OrderDetail OrderID="1" ProductID="3" Price="103.00" /> 6: <OrderDetail OrderID="1" ProductID="4" Price="104.00" /> 7: <OrderDetail OrderID="1" ProductID="5" Price="105.00" /> 8: </Order> 9: <Order ID="2" PersonID="1"> 10: <OrderDetail OrderID="2" ProductID="1" Price="101.00" /> 11: <OrderDetail OrderID="2" ProductID="2" Price="102.00" /> 12: <OrderDetail OrderID="2" ProductID="3" Price="103.00" /> 13: </Order> 14: <Order ID="3" PersonID="2"> 15: <OrderDetail OrderID="3" ProductID="1" Price="101.00" /> 16: <OrderDetail OrderID="3" ProductID="2" Price="102.00" /> 17: <OrderDetail OrderID="3" ProductID="3" Price="103.00" /> 18: </Order> 19: </Record>
调整下查询列的顺序,再看下结果,变了啊：
SELECT OrderDetail.OrderID, OrderDetail.ProductID, OrderDetail.Price, [Order].ID, [Order].PersonID FROM [Order] INNER JOIN OrderDetail ON [Order].ID = OrderDetail.OrderID FOR XML AUTO,ROOT('Record')
输出结果很猛：
<Record> <OrderDetail OrderID="1" ProductID="1" Price="101.00"> <Order ID="1" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="1" ProductID="2" Price="102.00"> <Order ID="1" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="1" ProductID="3" Price="103.00"> <Order ID="1" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="1" ProductID="4" Price="104.00"> <Order ID="1" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="1" ProductID="5" Price="105.00"> <Order ID="1" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="2" ProductID="1" Price="101.00"> <Order ID="2" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="2" ProductID="2" Price="102.00"> <Order ID="2" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="2" ProductID="3" Price="103.00"> <Order ID="2" PersonID="1" /> </OrderDetail> <OrderDetail OrderID="3" ProductID="1" Price="101.00"> <Order ID="3" PersonID="2" /> </OrderDetail> <OrderDetail OrderID="3" ProductID="2" Price="102.00"> <Order ID="3" PersonID="2" /> </OrderDetail> <OrderDetail OrderID="3" ProductID="3" Price="103.00"> <Order ID="3" PersonID="2" /> </OrderDetail> </Record>
XML结构变了,是变了,MSDN中是这样解释滴： 第一个ID引用自Order表,故创建Order节点，PersonID同样引用自Order表,第一步已经创建Order节点,故此处仅为节点添加PersonID属性。 接下来三列OrderID,ProductID,Price引用OrderDetail表,因此在Order节点下创建OrderDetail子节点 列的别名显示为属性名称,没有别名使用列名，节点的名称使用表别名,没有别名使用表名。 Order By对XML结构的影响 再看个例子,对Order.PersonID排序: SELECT [Order].ID, [Order].PersonID, OrderDetail.OrderID, OrderDetail.ProductID, OrderDetail.Price FROM [Order] INNER JOIN OrderDetail ON [Order].ID = OrderDetail.OrderID ORDER BY [Order].PersonId FOR XML AUTO,ROOT('Record')
输出结果： <Record> <Order ID="1" PersonID="1"> <OrderDetail OrderID="1" ProductID="1" Price="101.00" /> <OrderDetail OrderID="1" ProductID="2" Price="102.00" /> <OrderDetail OrderID="1" ProductID="3" Price="103.00" /> <OrderDetail OrderID="1" ProductID="4" Price="104.00" /> <OrderDetail OrderID="1" ProductID="5" Price="105.00" /> </Order> <Order ID="2" PersonID="1"> <OrderDetail OrderID="2" ProductID="1" Price="101.00" /> <OrderDetail OrderID="2" ProductID="2" Price="102.00" /> <OrderDetail OrderID="2" ProductID="3" Price="103.00" /> </Order> <Order ID="3" PersonID="2"> <OrderDetail OrderID="3" ProductID="1" Price="101.00" /> <OrderDetail OrderID="3" ProductID="2" Price="102.00" /> <OrderDetail OrderID="3" ProductID="3" Price="103.00" /> </Order> </Record>
其实这个结果与第一个查询结果是一样滴,行默认顺序会影响XML结果,排序也会影响XML结构,只要当前行与上一行数据可以合并时,就会影响XML结构，再来看一个排序影响XML结构的例子,这次以OrderDetail.ProductID排序,直接看结果： <Record> <Order ID="1" PersonID="1"> <OrderDetail OrderID="1" ProductID="1" Price="101.00" /> </Order> <Order ID="2" PersonID="1"> <OrderDetail OrderID="2" ProductID="1" Price="101.00" /> </Order> <Order ID="3" PersonID="2"> <OrderDetail OrderID="3" ProductID="1" Price="101.00" /> <OrderDetail OrderID="3" ProductID="2" Price="102.00" /> </Order> <Order ID="2" PersonID="1"> <OrderDetail OrderID="2" ProductID="2" Price="102.00" /> </Order> <Order ID="1" PersonID="1"> <OrderDetail OrderID="1" ProductID="2" Price="102.00" /> <OrderDetail OrderID="1" ProductID="3" Price="103.00" /> </Order> <Order ID="2" PersonID="1"> <OrderDetail OrderID="2" ProductID="3" Price="103.00" /> </Order> <Order ID="3" PersonID="2"> <OrderDetail OrderID="3" ProductID="3" Price="103.00" /> </Order> <Order ID="1" PersonID="1"> <OrderDetail OrderID="1" ProductID="4" Price="104.00" /> <OrderDetail OrderID="1" ProductID="5" Price="105.00" /> </Order> </Record>
以上就是FOR XML AUTO的应用的相关知识，本文我们就介绍到这里了，希望本次的介绍能够对您有所收获！