Hello,
I'm trying to write a function that needs to extract a value from a string containing an XML document. I don't have XML columns in my DB but just strings also for XML, for historical reasons.
I don't have much experience with XMLQUERY so I would code my function like this, but it doesn't compile:

create function extractField
(in p_fieldName varchar(8000),
in p_fieldNumber integer,
in p_fieldsXml clob
)
returns clob
begin
return XMLCAST(XMLQUERY( '$FLD/ObjectFields[Name=$FLD_NAME,Number=$FLD_NUMBER]/Contents[1]'
PASSING p_fieldsXml AS "FLD",
p_fieldName AS "FLD_NAME",
p_fieldNumber AS "FLD_NUMBER") as clob) ;
end

For example, if you pass the string
'<?xml version="1.0" encoding="UTF-8"?>
<Object>
<Fields>
<Name>Name</Name>
<Number>0</Number>
<Contents>DNS Name</Contents>
</Fields>
<Fields>
<Name>SMIME</Name>
<Number>0</Number>
<Contents>My content</Contents>
</Fields>
</Object>'
as p_fieldsXml,
'Name' as p_fieldName and
0 as p_fieldNumber

the output of the function should be: 'DNS Name'

Could you please suggest the correct implementation for this?

Before trying to compile a function, make sure your standalone expression works. You can use the VALUES statement to verify that in the command line processor.