Basic sql doubt

Question

hi all
observe the below query
SELECT RTRIM(XMLAGG(xmlelement (e,ename,',')).EXTRACT('//text()')) a
FROM EMP
group by deptno
it gives output as below
A
KING,MILLER,CLARK,
JONES,ADAMS,SMITH,FORD,SCOTT,
BLAKE,JAMES,TURNER,MARTIN,WARD,ALLEN,
CF_TYPE,CF_TYPE,CF_TYPE,
in the above output fourth row is having duplicate names
but i need to avoid duplicates and print all distinct as below
A
KING,MILLER,CLARK,
JONES,ADAMS,SMITH,FORD,SCOTT,
BLAKE,JAMES,TURNER,MARTIN,WARD,ALLEN,
CF_TYPE,Please help me on this.
am using oracle Application Express 4.0.2.00.08thanks for all in advance

Answer 1

Hi,
WITH data AS
     SELECT deptno, ename, DENSE_RANK() OVER (PARTITION BY deptno ORDER BY  ename) rn
     FROM   emp
     SELECT DISTINCT deptno, LTRIM(SYS_CONNECT_BY_PATH(ename,','),',') ename 
     FROM   data
     WHERE  CONNECT_BY_ISLEAF = 1
     CONNECT BY PRIOR rn + 1 = rn
     AND PRIOR deptno = deptno
     START WITH rn = 1
     ;