PostgresSQL xpath with namespaces - sql

Question

I would like to know how to use the xpath funtion in the following example:
The xml is inside a table called SR_DATA, field XMLDATA of type TEXT
The following is the structure of the xml document:
<?xml version="1.0" encoding="UTF-8"?>
<modulo modelCodeScheme="DocType" modelCodeSchemeVersion="01" modelCodeValue="TYPE_20a" modelCodeMeaning="SCREENING" group="groupname" type="format" xmlns="http://www.expr.com/2008/FMSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<AAAAA modelCodeScheme="MAM" modelCodeSchemeVersion="1" modelCodeValue="AN_MAM_6" modelCodeMeaning="Family1" tipodato="booleano">
<![CDATA[false]]>
</AAAAA>
<BBBBB modelCodeScheme="MAM" modelCodeSchemeVersion="1" modelCodeValue="AN_MAM_8" modelCodeMeaning="Family2" tipodato="booleano">
<![CDATA[false]]>
</BBBBB>
</modulo>
Let's say I want to read the text about the element named AAAAA, so my query looks like this:
SELECT (xpath('/modulo/AAAAA/text()', XMLDATA::xml) AS status
FROM SR_DATA;
My query doesn't raise any error but the resultset is empty; I suppose I have to map the NAMESPACES but I need a hint on how to do it.

Answer 1

You need to specify namespaces in the xpath function. The node contains multiple text nodes; you could combine the nodes together using array_to_string function:
SELECT TRIM(BOTH FROM array_to_string(xpath('/x:modulo/x:AAAAA/text()', XMLDATA::xml, ARRAY[
ARRAY['x', 'http://www.expr.com/2008/FMSchema']
]), ''))
FROM SR_DATA
-- false
Demo on db<>fiddle