从预言机中的重复节点中提取特定的xml节点

Question

给定是"XYZ"表中"my_xml"列的值

<?xml version="1.0" encoding="UTF-8"?>
<India>
  <city>
    <string>ADI</string>
    <string>Ahmedabad</string>
  </city>
  <city>
    <string>GNR</string>
    <string>Gandhinagar</string>
  </city>
  <city>
    <string>PUN</string>
    <string>Pune</string>
  </city>
  <city>
    <string>RJT</string>
    <string>Rajkot</string>
  </city>
</India>

我正在尝试提取第二个string节点的值，其中第一个string节点值ADI

输出应仅为"艾哈迈达巴德"

失败的尝试：

select t.my_xml.extract('/India/city/string[2]/text()').getStringVal() from XYZ t where t.my_xml.existsNode('/India/city[string[1] = "ADI"]') = 1;

上述查询的输出AhmedabadGandhinagarPuneRajkot

预期输出：Ahmedabad

如何在此处提取string节点的特定节点值？

Answer 1

你想要选择将 ADI 文本作为第一个字符串的节点。

试试这个：

select 
    t.my_xml.extract('//city[./string[1]/text() = "ADI"]/string[2]/text()').getStringVal()
from XYZ t
    where t.my_xml.existsNode('/India/city[string[1] = "ADI"]') = 1;

Answer 2

使用 XMLTable 提取值：

SELECT t.*
FROM   XYZ x,
       XMLTable(
         '/India/city'
         PASSING x.my_xml
         COLUMNS string1 CHAR(3)      PATH './string[1]',
                 string2 VARCHAR2(20) PATH './string[2]'
       ) t
WHERE  t.string1 = 'ADI';

Answer 3

1） 使用 xmlquery 和 flwor xquery

select xmlcast( xmlquery('for $i in ./India/city where $i//string[1]/text() = $cond return $i/string[2]/text()' passing xmltype(q'~<India>
  <city>
    <string>ADI</string>
    <string>Ahmedabad</string>
  </city>
  <city>
    <string>GNR</string>
    <string>Gandhinagar</string>
  </city>
  <city>
    <string>PUN</string>
    <string>Pune</string>
  </city>
  <city>
    <string>RJT</string>
    <string>Rajkot</string>
  </city>
</India>~'), 'ADI' as "cond"    returning content) as varchar2(20)) result  from dual; 

2）如果您期望多行，请尝试xmltable。

select *  from xmltable('$doc/India/city' passing xmltype(q'~<India>
  <city>
    <string>ADI</string>
    <string>Ahmedabad</string>
  </city>
  <city>
    <string>GNR</string>
    <string>Gandhinagar</string>
  </city>
  <city>
    <string>PUN</string>
    <string>Pune</string>
  </city>
   <city>
    <string>ADI</string>
    <string>Ahmedabad</string>
  </city>
  <city>
    <string>RJT</string>
    <string>Rajkot</string>
  </city>
</India>~') as "doc" 
columns 
   string1 varchar2(20) path'./string[1]/text()'
   , string2 varchar2(20) path'./string[2]/text()'
)
where string1='ADI'

和 xmltable with flwor xquery

select column_value  from xmltable('for $el in $doc/India/city where $el//string[1]/text() = "ADI" return $el/string[2]/text()' passing xmltype(q'~<India>
  <city>
    <string>ADI</string>
    <string>Ahmedabad</string>
  </city>
  <city>
    <string>GNR</string>
    <string>Gandhinagar</string>
  </city>
  <city>
    <string>PUN</string>
    <string>Pune</string>
  </city>
   <city>
    <string>ADI</string>
    <string>Ahmedabad</string>
  </city>
  <city>
    <string>RJT</string>
    <string>Rajkot</string>
  </city>
</India>~') as "doc" )
;