如何将XML编码标签附加到XML结果集

Question

我从下面的SQL代码出现两个问题：

DECLARE @tbl TABLE(BookID int primary key, 
        Title varchar(50), 
        Author varchar(50), 
        Pages int); 

INSERT INTO @tbl SELECT 1,'The Book', 'The Author', 20 
INSERT INTO @tbl SELECT 2,'Another Book', 'Another Author', 20 
INSERT INTO @tbl SELECT 3,'Book', 'Author', 20 

SELECT Book.Title, 
     (SELECT Details.BookID Ref, Details.Author, Details.Pages 
     FROM @tbl Details 
     FOR XML RAW ('Details'), type) 
FROM @tbl Book 
FOR XML RAW ('Book'), ROOT ('Books') 

返回的结果集为：

<Books> 
    <Book Title="The Book"> 
    <Details Ref="1" Author="The Author" Pages="20" /> 
    <Details Ref="2" Author="Another Author" Pages="20" /> 
    <Details Ref="3" Author="Author" Pages="20" /> 
    </Book> 
    <Book Title="Another Book"> 
    <Details Ref="1" Author="The Author" Pages="20" /> 
    <Details Ref="2" Author="Another Author" Pages="20" /> 
    <Details Ref="3" Author="Author" Pages="20" /> 
    </Book> 
    <Book Title="Book"> 
    <Details Ref="1" Author="The Author" Pages="20" /> 
    <Details Ref="2" Author="Another Author" Pages="20" /> 
    <Details Ref="3" Author="Author" Pages="20" /> 
    </Book> 
</Books> 

问题一：详细标签对于每本书都重复多次，我只需要一个。 第2期：我想将<?xml version="1.0"?>附加到结果集的顶部。

Answer 1

可能有多种方法可以做到这一点。这里是一个：

DECLARE @tbl TABLE(BookID int primary key, 
       Title varchar(50), 
       Author varchar(50), 
       Pages int); 

INSERT INTO @tbl SELECT 1,'The Book', 'The Author', 20 
INSERT INTO @tbl SELECT 2,'Another Book', 'Another Author', 20 
INSERT INTO @tbl SELECT 3,'Book', 'Author', 20 


;WITH cte (XMLRESULT) AS (

SELECT Book.Title, 
    (SELECT Details.BookID Ref, Details.Author, Details.Pages 
    FROM @tbl Details 
    FOR XML RAW ('Details'), type) 
FROM @tbl Book 
FOR XML RAW ('Book'), ROOT ('Books') 

) 

SELECT '<?xml version="1.0"?>' + XMLRESULT FROM cte 

Answer 2

第一个问题是很容易被添加WHERE条款列入子查询处理：

SELECT Book.Title, 
     (SELECT Details.BookID Ref, Details.Author, Details.Pages 
     FROM @tbl Details 
     WHERE Details.BookID = Book.BookID --<-- Here 
     FOR XML RAW ('Details'), type) 
FROM @tbl Book 
FOR XML RAW ('Book'), ROOT ('Books') 

回复：XML声明，我不知道这是那么容易实现的 - 大多数人似乎将解决这个问题转换为文本，只是干扰正面的字符串。