Tsql 如何将CTE与FOR XML子句组合？

我正在尝试生成一些具有不同嵌套级别的XML，并且冒着过度简化的风险，输出XML的格式将松散：

<invoice number="1">
 <charge code="foo" rate="123.00">
  <surcharge amount="10%" />
 </charge>
 <charge code="bar" />
</invoice>

现在，这是难以置信的接近，给出（注意嵌套的

）：

---

但我需要找到一种方法，使结束查询包含XML列的值，该列将被视为元素的内容，而不是新元素。这是可能的，还是我需要采取一种新的方法？

我认为可以通过省略“for xml path（'overload'）”语句中的根节点类型来做到这一点。也就是说，使用“for xml path（“”）”。

您有一个列查询，它返回多行（@charge、@rate和一个xml类型）。我希望您发布的查询会给出错误：

---

只能指定一个表达式 在选择列表中，当子查询 不与EXISTS一起引入

但是，通过将查询移动到

外部应用

，可以很容易地解决这个问题。要删除double

supployee

元素，可以将XML列名尽可能地移到底部，如：

;WITH Charges (code, rate, surcharge, InvoiceId) AS 
    (
    SELECT  code, amount, NULL, InvoiceId
    FROM    @charges
    UNION ALL
    SELECT  code
    ,       amount
    ,       (
            SELECT  amount AS [@amount]
            FROM    @surcharges os
            WHERE   oc.ChargeId = os.ChargeId
            FOR XML PATH('surcharge'), TYPE
            )
    ,       InvoiceId
    FROM    @charges oc
)
SELECT  Number AS [@number]
,       c.code as [charge/@code]
,       c.rate as [charge/@rate]
,       c.surcharge as [charge]
FROM    @Invoices i
outer apply
        (
        SELECT  code
        ,       rate
        ,       surcharge
        FROM    Charges
        WHERE   Charges.InvoiceId = i.InvoiceId
        ) c
WHERE   i.InvoiceID = 1
FOR XML PATH( 'invoice' ), TYPE

这将打印，例如：

<invoice number="1">
  <charge code="1" rate="1" />
</invoice>
<invoice number="1">
  <charge code="1" rate="1">
    <surcharge amount="1" />
  </charge>
</invoice>

---

第一个元素来自联合体的顶部，其中

assemployment=null

似乎将（假）列命名为“*”将使用该列的内容作为元素的内容，因此按以下方式更改SQL使其工作：

WITH Charges ( [@code], [@rate], surcharge, InvoiceId ) AS (
    SELECT code AS [@Code], amount AS [@rate], NULL as surcharge, InvoiceId
    FROM item.charges
UNION ALL
    SELECT 
        code AS [@Code], 
        amount AS [@rate],
        (
             SELECT amount AS [@amount]
             FROM order.surcharges os
             WHERE oc.ChargeId = os.ChargeId
             FOR XML PATH('surcharge'), TYPE
        ), 
        InvoiceId
    FROM order.charges oc
)
SELECT
    Number AS [@number],
    (
         SELECT
             [@code],
             [@rate],
             surcharge AS [*] -- Thsi will embed the contents of the previously generated XML in here.
         FROM Charges
         WHERE Charges.InvoiceId = i.InvoiceId
    )
FROM Invoices i
FOR XML PATH( 'invoice' ), TYPE

---

这就产生了一个错误：“行标记省略（空行标记名称）不能与以属性为中心的XML序列化一起使用。”+1附加费是由位于联合体顶部的

NULL作为附加费隐式添加的，因此路径（'surgcharge'）看起来是重复的。我对该错误感到困惑。如果按照我建议的方式在联合体中使用“for xml”子句单独运行第二个select，会发生什么情况？如果子查询没有引入EXISTS，则select列表中只能指定一个表达式。@user3752281该解决方案对我有效，因此我不理解您的评论？
<invoice number="1">
  <charge code="1" rate="1" />
</invoice>
<invoice number="1">
  <charge code="1" rate="1">
    <surcharge amount="1" />
  </charge>
</invoice>

WITH Charges ( [@code], [@rate], surcharge, InvoiceId ) AS (
    SELECT code AS [@Code], amount AS [@rate], NULL as surcharge, InvoiceId
    FROM item.charges
UNION ALL
    SELECT 
        code AS [@Code], 
        amount AS [@rate],
        (
             SELECT amount AS [@amount]
             FROM order.surcharges os
             WHERE oc.ChargeId = os.ChargeId
             FOR XML PATH('surcharge'), TYPE
        ), 
        InvoiceId
    FROM order.charges oc
)
SELECT
    Number AS [@number],
    (
         SELECT
             [@code],
             [@rate],
             surcharge AS [*] -- Thsi will embed the contents of the previously generated XML in here.
         FROM Charges
         WHERE Charges.InvoiceId = i.InvoiceId
    )
FROM Invoices i
FOR XML PATH( 'invoice' ), TYPE