How to retrieve specific data from XML in Oracle table

Question

I have an oracle table which has a column that stores XML. The XML has the following syntax:

<?xml version="1.0"?>
<MessageData>
  <TextblockParameters>
    <TextblockParameter>
      <tagName>BUSINESSPROCESSID</tagName>
      <value>RETAIL</value>
    </TextblockParameter>
    <TextblockParameter>
      <tagName>SEGMENT</tagName>
      <value>RESIDENTIAL</value>
    </TextblockParameter>
    <TextblockParameter>
      <tagName>TRANSACTIONTYPE</tagName>
      <value>PURCHASE</value>
    </TextblockParameter>
    <TextblockParameter>
      <tagName>LANGUAGE</tagName>
      <value>EST</value>
    </TextblockParameter>
  </TextblockParameters>
</MessageData>

Now i need to get info from <value></Value>, from all 4 places. Please help with this issue, dont know if Extractvalue is best solution

Answer 1

You can use XMLTABLE function for this (see examples):

SELECT t.foo, xt.*
FROM t, XMLTABLE('//TextblockParameter'
    PASSING t.xmlcol
    COLUMNS
        tagName VARCHAR2(100) PATH './tagName',
        value VARCHAR2(100) PATH './value'
) xt;

Demo on db<>fiddle

Answer 2

you can use

select extract(col1, '//value') from t;

create table t (col1 xmltype);

✓

insert into t values ('
<MessageData>
  <TextblockParameters>
    <TextblockParameter>
      <tagName>BUSINESSPROCESSID</tagName>
      <value>RETAIL</value>
    </TextblockParameter>
    <TextblockParameter>
      <tagName>SEGMENT</tagName>
      <value>RESIDENTIAL</value>
    </TextblockParameter>
    <TextblockParameter>
      <tagName>TRANSACTIONTYPE</tagName>
      <value>PURCHASE</value>
    </TextblockParameter>
    <TextblockParameter>
      <tagName>LANGUAGE</tagName>
      <value>EST</value>
    </TextblockParameter>
  </TextblockParameters>
</MessageData>');

1 rows affected

select extract(col1, '//value') from t;

| EXTRACT(COL1,'//VALUE')                                                                                  |
| :------------------------------------------------------------------------------------------------------- |
| <value>RETAIL</value><br><value>RESIDENTIAL</value><br><value>PURCHASE</value><br><value>EST</value><br> |

db<>fiddle here