วิธีแก้ select xml data จาก oracle database (ORA-19025: EXTRACTVALUE returns value of only) โดยใช้ xmlsequence

SELECT  extractValue(y.column_value, '/C_CUST_OWNER/@id') cust_id
FROM    tbl_item_po_xml t,table (xmlsequence(extract(t.xml_data,'/INTERNAL_PRD_CODES/INTERNAL_PRD_CODE/WAREHOUSE_NOS/WAREHOUSE_NO'))) x,table (xmlsequence(extract(x.column_value,'/WAREHOUSE_NO/C_CUST_OWNERS/C_CUST_OWNER'))) y
WHERE   C_FILE_NAME = c_file_name
AND     extractValue(t.xml_data, '/INTERNAL_PRD_CODES/INTERNAL_PRD_CODE/@id') = j.prd_code
AND     extractValue(x.column_value, '/WAREHOUSE_NO/@id') = k.wh_no