从 oracle 中的重复节点中提取特定 xml 节点

Question

给出的是 "XYZ" table

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 节点的值为 ADI

输出应该只有 "Ahmedabad"

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;

上述查询的输出是AhmedabadGandhinagarPuneRajkot

预期输出：Ahmedabad

如何在此处提取 string 节点的特定节点值？

Answer 1

您想select具有 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) 如果您希望多行，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'

和带有 flwor xquery 的 xmltable

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" )
;

从 oracle 中的重复节点中提取特定 xml 节点

Extract specific xml node from duplicate ones in oracle

xml

sql

oracle

extract

oracle-xml-db