我如何使用SQL和列值转换为XML元素名称FOR XML

Question

我在MyTable的表行：

MessageID EMailAddress  DisplayName RecipientType 
1   joe@email.com  Joe   To 
1,  Bob@email.com  Max   From 
1,  Max@email.com  NULL  To 
1,  Secret@email.com Secret  Bcc 

我试图将其转换为XML，看起来像下面这样：

<to> 
    <displayName>Joe</displayName> 
    <address>joe@email.com</address> 
</to> 
<from> 
    <displayName>Bob</displayName> 
    <address>Bob@email.com</address> 
</from> 
<to> 
    <address>Max@email.com</address> 
</to> 
<bcc> 
    <displayName>Secret</displayName> 
    <address>Secret@email.com</address> 
</bcc> 

我很接近，但无法弄清楚如何将RecipientType转换成父元素的另外两列

SELECT 
a.EmailAddress as address, 
a.DisplayName as displayName 
FROM MyTable a 
WHERE a.Id = 1 
FOR XML PATH('address'), TYPE 

有没有办法让“FOR XML PATH（'address'）”成为RecipientType而不是硬编码的'地址'？还是有另一种选择？

我也试过玩过PIVOT，但它似乎没有帮助。

我知道我可以使用动态SQL，但我试图远离那个。

Answer 1

with data as (
    select * from (
    values (1, 'joe@email.com', 'Joe', 'To', 1), 
      (1, 'Bob@email.com', 'Bob', 'From', 2), 
      (1, 'Max@email.com', null, 'To', 3), 
      (1, 'Secret@email.com', 'Secret', 'Bcc', 4) 
    ) t(MessageID, EMailAddress, DisplayName, RecipientType, Ordering) 
    where MessageID = 1 
), pivoted as (
    select * 
    from data pivot (max(EmailAddress) for RecipientType in ([To], [From], [Bcc])) t 
) 
select (case when [To] is not null then DisplayName else null end) as 'to/displayName', [To] as 'to/address', 
     (case when [From] is not null then DisplayName else null end) as 'from/displayName', [From] as 'from/address', 
     (case when [Bcc] is not null then DisplayName else null end) as 'bcc/displayName', [Bcc] as 'bcc/address' 
from pivoted 
order by Ordering 
for xml path('') 

Answer 2

也许这可以让你开始： 我认为你将需要一个元素，不管。

DECLARE @data XML; 

SET @data = 

N' 
<root> 
<to> 
    <displayName>Joe</displayName> 
    <address>joe@email.com</address> 
</to> 
<from> 
    <displayName>Bob</displayName> 
    <address>Bob@email.com</address> 
</from> 
<to> 
    <address>Max@email.com</address> 
</to> 
<bcc> 
    <displayName>Secret</displayName> 
    <address>Secret@email.com</address> 
</bcc> 
</root>'; 




SELECT 
     T.myAlias.value('(.)[1]', 'VARCHAR(32)') AS emailAddress 
    , T.myAlias.value('fn:local-name(..)', 'nvarchar(50)') as t 
FROM 
    @data.nodes('//address') AS T(myAlias) 
where 
    T.myAlias.value('fn:local-name(..)', 'nvarchar(50)') = 'to' 
; 

结果：

emailAddress      t 
-------------------------------- -------------------------------------------------- 
joe@email.com     to 
Max@email.com     to 

---

SELECT 

     T.myAlias.value('(.)[1]', 'VARCHAR(32)') AS emailAddress 
    , T.myAlias.value('(../displayName)[1]', 'VARCHAR(32)') AS displayName 
    , T.myAlias.value('fn:local-name(..)', 'nvarchar(50)') as RecipientType 
FROM 
    @data.nodes('//address') AS T(myAlias) 

; 


emailAddress      displayName      RecipientType 
-------------------------------- -------------------------------- 
joe@email.com     Joe        to 
Bob@email.com     Bob        from 
Max@email.com     NULL        to 
Secret@email.com     Secret       bcc 

有除标识的一切。

一个问题，position（）在Xml Shredding中不完全支持。 ：<

http://connect.microsoft.com/SQLServer/feedback/details/383888/fully-support-position-in-xquery

，也看到了这个帖子：

Finding node order in XML document in SQL server