How to pass value in xmltable - sql

Question

How can I pass a variable value inside the xpath of xmltable?
DECLARE
v NUMBER := 0;
BEGIN
SELECT *
FROM xml_billrun_files t ,
xmltable('/invoice/AR_ITEMS[#elem='||v||']/ITEMS/USAGE_RECORDS/SESSION_INFO'
passing t.update_xmldoc
columns chrg_duration VARCHAR2(20) path 'DURATION',
amount NUMBER path 'AMOUNT') x;
END;
I've tried this one.
DECLARE
v NUMBER := 0;
BEGIN
SELECT *
FROM xml_billrun_files t ,
xmltable('/invoice/AR_ITEMS[#elem=$i]/ITEMS/USAGE_RECORDS/SESSION_INFO'
passing t.update_xmldoc, xmltype(v) as "i"
columns chrg_duration VARCHAR2(20) path 'DURATION',
amount NUMBER path 'AMOUNT') x;
END;
But it returns an error:
ORA-31011: XML parsing failed
ORA-19202: Error occurred in XML processing
LPX-00210: expected '<' instead of '0'
Error at line 1
ORA-06512: at "SYS.XMLTYPE", line 310
ORA-06512: at line 1
ORA-06512: at line 5
31011. 00000 - "XML parsing failed"
*Cause: XML parser returned an error while trying to parse the document.
*Action: Check if the document to be parsed is valid.
thanks for the help.

Answer 1

In my answer to your previous question, I incorrectly used xmltype(lp) as "lp" for your XMLQuery call. Not sure why it didn't complain there, but it didn't actually restrict the match anyway...
For this XMLTable call you can pass the number directly, without conversion/cast, as it's already a number:
SELECT chrg_duration, amount
into ...
FROM xml_billrun_files t ,
xmltable('/invoice/AR_ITEMS[#elem=$i]/ITEMS/USAGE_RECORDS/SESSION_INFO'
passing t.update_xmldoc, v as "i"
columns chrg_duration VARCHAR2(20) path 'DURATION',
amount NUMBER path 'AMOUNT') x;
If you're doing it in a for loop, then the index is the wrong data type, and you need to cast it to number:
SELECT chrg_duration, amount
into ...
FROM xml_billrun_files t ,
xmltable('/invoice/AR_ITEMS[#elem=$i]/ITEMS/USAGE_RECORDS/SESSION_INFO'
passing t.update_xmldoc, cast(v as number) as "i"
columns chrg_duration VARCHAR2(20) path 'DURATION',
amount NUMBER path 'AMOUNT') x;