XML Generation Using DBMS_XMLQuery

Question

Hi,
I am generating XML using "DBMS_XMLQuery".
Requirement: To generate blank xml tag(Without data).
e.g : Table XXX has A,B,C,D columns.
I am using SQL : SELECT a AA,b BB,c CC,d DD FROM XXX;
<AA>1 </AA>
<BB>2 </BB>
<CC>3 </CC>
(Note : Columns A,B and C has Values but "d" column does not have value).
Since "D" column doesnot have value,it is not generating XML tag.
So ,How to generate XML tag(e.g <DD> </DD>) without Value?
Any idea,how to achieve the above?
Thanks in advance.
Rgds,
Manoj
==========================
<?xml version = '1.0'?>
<ORDERS>
<ORDER num="1">
<MESSAGE_ID>1</MESSAGE_ID>
<SOURCE_SYSTEM>Oracle</SOURCE_SYSTEM>
<OPERATION>OrderRMA</OPERATION>
<DATETIME>3/21/2006 15:30:44</DATETIME>
<VERSION>1</VERSION>
<COUNTRY>AUS</COUNTRY>
<LANGUAGE>ENG</LANGUAGE>
<DESTINATION_SYSTEM>Manhattan</DESTINATION_SYSTEM>
<DESTINATION_WAREHOUSE>AUSVIS</DESTINATION_WAREHOUSE>
<ORDER_HEADER>
<ORDER_HEADER_ROW num="1">
----

Answer 1

You can set the null attribute to true , so that the tag appears in your XML
see the statement in Bold.
DECLARE
queryCtx dbms_xmlquery.ctxType;
result CLOB;
BEGIN
-- set up the query context
queryCtx := dbms_xmlquery.newContext(
'SELECT empno "EMP_NO"
, ename "NAME"
, deptno "DEPT_NO"
, comm "COMM"
FROM scott.emp
WHERE deptno = :DEPTNO'
dbms_xmlquery.setRowTag(
queryCtx
, 'EMP'
dbms_xmlquery.setRowSetTag(
queryCtx
, 'EMPSET'
DBMS_XMLQUERY.useNullAttributeIndicator(queryCtx,true);
dbms_xmlquery.setBindValue(
queryCtx
, 'DEPTNO'
, 30
result := dbms_xmlquery.getXml(queryCtx);
insert into clobtable values(result);commit;
dbms_xmlquery.closeContext(queryCtx);
END;
select * from clobtable
<?xml version = '1.0'?>
<EMPSET>
<EMP num="1">
<EMP_NO>7499</EMP_NO>
<NAME>ALLEN</NAME>
<DEPT_NO>30</DEPT_NO>
<COMM>300</COMM>
</EMP>
<EMP num="2">
<EMP_NO>7521</EMP_NO>
<NAME>WARD</NAME>
<DEPT_NO>30</DEPT_NO>
<COMM>500</COMM>
</EMP>
<EMP num="3">
<EMP_NO>7654</EMP_NO>
<NAME>MARTIN</NAME>
<DEPT_NO>30</DEPT_NO>
<COMM>1400</COMM>
</EMP>
<EMP num="4">
<EMP_NO>7698</EMP_NO>
<NAME>BLAKE</NAME>
<DEPT_NO>30</DEPT_NO>
<COMM NULL="YES"/>
</EMP>
<EMP num="5">
<EMP_NO>7844</EMP_NO>
<NAME>TURNER</NAME>
<DEPT_NO>30</DEPT_NO>
<COMM>0</COMM>
</EMP>
<EMP num="6">
<EMP_NO>7900</EMP_NO>
<NAME>JAMES</NAME>
<DEPT_NO>30</DEPT_NO>
<COMM NULL="YES"/>
</EMP>
</EMPSET>
http://sqltech.cl/doc/oracle9i/appdev.901/a89852/d_xmlque.htm