如何在 SQL Server 中使用 XPath、XQuery 使 XML 值以逗号分隔 [英] How to make XML values comma separated using XPath, XQuery in SQL Server

问题描述

我有一个 XML 列，其中的示例值为

I have an XML column with sample values as

<error>
  <errorno>BL04002055</errorno>
  <description>Smart Rule PROJECT_COUNTRYCODE_VAL Violated</description>
  <description2>Country Code is required</description2>
  <correction />
</error>
<error>
  <errorno>BL01001973</errorno>
  <description />
  <description2>Error While Saving the Project info</description2>
  <correction />
</error>
<error>
  <errorno>Unable to Create Custom Object</errorno>
  <description />
  <description2>Smart Rule PROJECT_COUNTRYCODE_VAL Violated: Country Code is required
Error While Saving the Project info</description2>
  <correction />
</error>

我想选择以逗号分隔的 description2 值

I want to select description2 values comma separated

select *
--, Response.value(''/error/description2/text()'', 'varchar(8000)') as parsedString
, Response.query('/error/description2/text()') as parsedString
 from #temp

这里有两个问题.

1. 我无法在上面的查询中运行值函数.
2. 使用查询，我得到了没有空格或逗号的值.所以我需要在连接的值上添加一些空格或逗号.

推荐答案

SQL Server 没有实现 xPath 函数 string-join，所以你需要采用两步过程，第一步是使用 nodes();

SQL Server does not implement the xPath function string-join, so you would need to adopt a two step process, the first would be to extract all the terms to rows using nodes();

SELECT  n.value('.', 'VARCHAR(100)') AS parsedString
FROM    #temp AS t
        CROSS APPLY t.Response.nodes('/error/description2') r (n);

它以行的形式为您提供值:

Which gives you your values as rows:

parsedString
----------------------------------------------------------------------------
Country Code is required
Error While Saving the Project info
Smart Rule PROJECT_COUNTRYCODE_VAL Violated: Country Code is required
Error While Saving the Project

然后您可以添加分隔符并将它们连接起来，使用 FOR XML PATH(''), TYPE，最后使用 STUFF 删除第一个分隔符:

Then you can add your delimeter and concatenate them back up, using FOR XML PATH(''), TYPE, and finally use STUFF to remove the first delimeter:

SELECT  STUFF(( SELECT  ',' + n.value('.', 'VARCHAR(100)') AS parsedString
                FROM    #temp AS t
                        CROSS APPLY t.Response.nodes('/error/description2') r (n)
                FOR XML PATH(''), TYPE
            ).value('.', 'VARCHAR(MAX)'), 1, 1, '') AS ParsedString;

<小时>

完整的工作示例

DECLARE @X XML = '<error>
  <errorno>BL04002055</errorno>
  <description>Smart Rule PROJECT_COUNTRYCODE_VAL Violated</description>
  <description2>Country Code is required</description2>
  <correction />
</error>
<error>
  <errorno>BL01001973</errorno>
  <description />
  <description2>Error While Saving the Project info</description2>
  <correction />
</error>
<error>
  <errorno>Unable to Create Custom Object</errorno>
  <description />
  <description2>Smart Rule PROJECT_COUNTRYCODE_VAL Violated: Country Code is required
Error While Saving the Project info</description2>
  <correction />
</error>';

SELECT  STUFF(( SELECT  ',' + n.value('.', 'VARCHAR(100)') AS parsedString
                FROM    (SELECT @X) AS t (Response)
                        CROSS APPLY t.Response.nodes('/error/description2') r (n)
                FOR XML PATH(''), TYPE
            ).value('.', 'VARCHAR(MAX)'), 1, 1, '') AS ParsedString;

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