XMLTable - Extract single row among 2 XML tags

Question

Hello,
Aim to extract the BRAND and its COST and I am able to extract with without any problem using XMLTable.
CREATE TABLE xml_tab (seqno number default 1, xml_data XMLType);
INSERT INTO xml_tab
VALUES
(1, XMLType('<PRODUCTS>
<LAPTOPS>
<NOTEBOOK BRAND="HP">1000</NOTEBOOK>
<NOTEBOOK BRAND="LENOVA">2000</NOTEBOOK>
</LAPTOPS>
</PRODUCTS>'));
SELECT t.seqno, tx.* FROM xml_tab t,
XMLTABLE('/PRODUCTS/LAPTOPS/NOTEBOOK' PASSING t.xml_data
COLUMNS brandname CHAR(20) PATH '@BRAND',
cost CHAR(20) PATH '.') tx
WHERE brandname in ('HP', 'LENOVA') AND seqno = 1;
Outpupt
SEQNO BRANDNAME COST
1 HP 1000
1 LENOVA 2000
Below query will demonstrate the problem I am facing and need your kind help to resovle it.
INSERT INTO xml_tab
VALUES
(2, XMLType('<PRODUCTS>
<LAPTOPS>
<NOTEBOOK BRAND="HP">3000</NOTEBOOK>
<NOTEBOOK BRAND="HP">1400</NOTEBOOK>
<NOTEBOOK BRAND="LENOVA">5000</NOTEBOOK>
</LAPTOPS>
</PRODUCTS>'));
(Below query is not working)
SELECT t.seqno, tx.* FROM xml_tab t,
XMLTABLE('/PRODUCTS/LAPTOPS/NOTEBOOK[1]' PASSING t.xml_data
COLUMNS brandname CHAR(20) PATH '@BRAND',
cost CHAR(20) PATH '.') tx
WHERE brandname in ('HP', 'LENOVA') AND seqno = 2;
My requirement is to display only single row of HP and LENOVA brand even if there are multiple XML tags of one brand. Therefore, desired output is*
SEQNO BRANDNAME COST
2 HP 3000
2 LENOVA 5000
Kindly suggest.
Thanks in advance
Sandeep
Edited by: Sandeep98191 on Sep 22, 2012 9:24 PM

Answer 1

WITH t as (
           SELECT  t.seqno,
                   tx.*,
                   row_number() over(partition by brandname order by rownum) rn
             FROM  xml_tab t,
                   XMLTABLE(
                            '/PRODUCTS/LAPTOPS/NOTEBOOK'
                            PASSING t.xml_data
                            COLUMNS
                              brandname CHAR(20) PATH '@BRAND',
                              cost CHAR(20) PATH '.'
                           ) tx
             WHERE brandname in ('HP', 'LENOVA')
               AND seqno = 2
select  seqno,
        brandname,
        cost
  from  t
  where rn = 1
     SEQNO BRANDNAME            COST
         2 HP                   3000
         2 LENOVA               5000
SQL> SY.