使用 XQUERY 节点函数将值提取到行中

Question

我的问题与此 one 相同，但我使用的是 Oracle 12.1 而不是 SQL 服务器。

我想从以下 xml 文档中提取所有名称元素：

<ci5>
   <employee>
      <name>George Cowley</name>  
      <salary via="B">80000</salary>
   </employee>
   <employee>
      <name>William Bodie</name>  
      <salary via="C">40000</salary>
   </employee>
   <employee>
      <name>Ray Doyle</name>  
      <salary via="C">40000</salary>
   </employee>
</ci5>

我想要的输出是三个单独的行，例如：

<name>George Cowley</name>
<name>William Bodie</name>
<name>Ray Doyle</name>

使用以下查询

SELECT XMLQUERY('ci5/employee/name' 
                  PASSING BY VALUE XMLTYPE.CREATEXML('<ci5><employee><name>George Cowley</name><salary via="B">80000</salary></employee><employee><name>William Bodie</name><salary via="C">40000</salary></employee><employee><name>Ray Doyle</name><salary via="C">40000</salary></employee></ci5>') RETURNING CONTENT) x
   FROM dual;  

 SELECT XMLQUERY('for $i in /ci5
                 return $i/employee/name'
                 PASSING BY VALUE XMLTYPE.CREATEXML('<ci5><employee><name>George Cowley</name><salary via="B">80000</salary></employee><employee><name>William Bodie</name><salary via="C">40000</salary></employee><employee><name>Ray Doyle</name><salary via="C">40000</salary></employee></ci5>') RETURNING CONTENT) x
   FROM dual;

名称已显示，但输出全部在一行中：

<name>George Cowley</name><name>William Bodie</name><name>Ray Doyle</name>

看起来我需要使用 NODE 函数，但我不知道如何在 Oracle 上下文中使用它。

Answer 1

我认为您不需要为此使用任何 xquery。一个简单的 xpath 表达式就足够了。这里有两个选项。第一个 returns 一个 XML 序列（单独的 xml 个节点），第二个 returns 作为 table 行：

    WITH test AS
      (SELECT xmltype('<ci5>   
    <employee>      
    <name>George Cowley</name>        
    <salary via="B">80000</salary>   
    </employee>   
    <employee>      
    <name>William Bodie</name>        
    <salary via="C">40000</salary>   
    </employee>   
    <employee>      
    <name>Ray Doyle</name>        
    <salary via="C">40000</salary>   
    </employee>
    </ci5>  ') data
      FROM dual
      )
    SELECT xmlsequence(extract(data,'/ci5/employee/name')) FROM test

WITH test AS
      (SELECT xmltype('<ci5>   
    <employee>      
    <name>George Cowley</name>        
    <salary via="B">80000</salary>   
    </employee>   
    <employee>      
    <name>William Bodie</name>        
    <salary via="C">40000</salary>   
    </employee>   
    <employee>      
    <name>Ray Doyle</name>        
    <salary via="C">40000</salary>   
    </employee>
    </ci5>  ') data
      FROM dual
      )
    SELECT extract(value(d), '*') AS name
    FROM test,
      TABLE(xmlsequence(extract(data, '/ci5/employee/name'))) d

Answer 2

This Oracle white paper answered the question, I needed to use XMLTABLE 其中

...maps the result of an XQuery evaluation into relational rows and columns...

更改我的查询以使用 XMLTABLE

 SELECT x.ename
   FROM XMLTABLE('/ci5/employee/name'                 
                 PASSING XMLTYPE.CREATEXML('<ci5><employee><name>George Cowley</name><salary via="B">80000</salary></employee><employee><name>William Bodie</name><salary via="C">40000</salary></employee><employee><name>Ray Doyle</name><salary via="C">40000</salary></employee></ci5>') 
                 COLUMNS ename VARCHAR2(30) PATH '/name') x

在 SQL 开发人员中给出以下输出：

使用 XQUERY 节点函数将值提取到行中

Using the XQUERY node function to extract values into rows

oracle

xquery-sql

oracle-xml-db