9

我正在尝试获取 XML 字段中的节点数。但我总是看到 0 结果。这是我的查询的样子。


 DECLARE @XmlTable TABLE (XmlResult XML)
INSERT INTO @XmlTable EXECUTE [dbo].usp_GetBooks @EditionId=400
--select * from  @XmlTable
SELECT
--Count number of nodes
  COUNT(*) AS BooksCount
FROM
(
SELECT XmlResult FROM @XmlTable
) AS XmlTable(XmlColumn)
CROSS APPLY XmlColumn.nodes('./books/book') XmlTableFunction(XmlColumn2);

我的 XML 看起来像:

<Version number ="1"> 
<books>
<book>
  <name> </name>
  <author></author>
</book>
<book>
  <name> </name>
  <author></author>
</book>
</books>
</Version>
4

2 回答 2

29

我认为你的 XPath 表达式是错误的 - 试试这个:

DECLARE @XmlTable TABLE (XmlResult XML)

INSERT INTO @XmlTable EXECUTE [dbo].usp_GetBooks @EditionId=400

SELECT
    COUNT(*) AS BooksCount
FROM
   (SELECT XmlResult FROM @XmlTable) AS XmlTable(XmlColumn)
CROSS APPLY 
   XmlColumn.nodes('/Version/books/book') XmlTableFunction(XmlColumn2)

或者更简单:

DECLARE @XmlTable TABLE (XmlResult XML)

INSERT INTO @XmlTable EXECUTE [dbo].usp_GetBooks @EditionId=400

SELECT
    XmlResult.value('count(/Version/books/book)', 'int')
FROM
   @XmlTable
于 2011-03-25T22:04:37.500 回答
2

使用您提供的 XML 模式为我工作

DECLARE @XmlTable TABLE (XmlResult XML)
INSERT INTO @XmlTable VALUES ('<books><book><title>GWTW</title></book></books>')
INSERT INTO @XmlTable VALUES ('<foo />')
INSERT INTO @XmlTable VALUES ('<books />')
SELECT
  COUNT(*) AS BooksCount
FROM
(
SELECT XmlResult FROM @XmlTable
) AS XmlTable(XmlColumn)
CROSS APPLY XmlColumn.nodes('./books/book') XmlTableFunction(XmlColumn2);

Exist 方法也非常有用。我使用 NULLIF 将 0 更改为 NULL (它有点需要 CAST 和 SUM)

SELECT COUNT(NULLIF(XmlResult.exist('./books/book'), 0)) FROM @XmlTable

编辑,更新后

您发布的 XML 也是错误的。

您没有正确指定根音:

DECLARE @XmlTable TABLE (XmlResult XML)
INSERT INTO @XmlTable VALUES ('
<Version number ="1"> 
<books>
<book>
  <name> </name>
  <author></author>
</book>
<book>
  <name> </name>
  <author></author>
</book>
</books>
</Version>')
SELECT
  COUNT(*)
FROM
(
SELECT XmlResult FROM @XmlTable
) AS XmlTable(XmlColumn)
CROSS APPLY XmlColumn.nodes('/Version/books/book') XmlTableFunction(XmlColumn2);

SELECT
  COUNT(*)
FROM
(
SELECT XmlResult FROM @XmlTable
) AS XmlTable(XmlColumn)
CROSS APPLY XmlColumn.nodes('*/books/book') XmlTableFunction(XmlColumn2);
于 2011-03-25T21:50:38.663 回答