display odd / even records
To select ODD record
[sql]select max(rownum),empno,ename from emp GROUP BY rownum,empno,ename
having mod(rownum,2)<>0[/sql]

To select Even record
[sql]select max(rownum),empno,ename from emp GROUP BY rownum,empno,ename
having mod(rownum,2)=0[/sql]