Need to Concatenate Data In a Single Record

Question

Guys
Here I describe the example on the employee data
Before
10 ABC
10 SCOTT
10 KING
20 ROBERT
20 ALLEN
AFTER
10 ABC, SCOTT, KING
20 ROBERT, ALLEN
I had a requirement to concatenate employee name in single record by department wise, I have done by creating
function(Using loop) and call it in sql query, but query is getting much time,
Is there any other way to improve the query without using loop?
Kindly help me, Thanks in Advance.

Answer 1

SQL> ed
Wrote file afiedt.buf
  1  select deptno,
  2  LTRIM(max(sys_connect_by_path(ename,',')),',') employess
  3  from (select deptno,ename,
  4        row_number() over(partition by emp.deptno
  5        order by empno) r
  6        from emp)
  7  start with r=1
  8  connect by prior r+1=r
  9         and prior deptno=deptno
10* group by deptno
SQL> /
    DEPTNO
EMPLOYESS
        30
ALLEN,WARD,MARTIN,BLAKE,TURNER,JAMES
        20
SMITH,JONES,SCOTT,ADAMS,FORD
        10
CLARK,KING,MILLERFor more example
http://www.oracle-base.com/articles/misc/StringAggregationTechniques.php