select x.ename
from (
select a.ename,
(select count(*)
from emp b
where b.ename <=a.ename) as rn
from emp a
) x
where mod(x.rn,2) =1;
select x.ename
from (
select a.ename,
(select count(*)
from emp b
where b.ename <=a.ename) as rn
from emp a
) x
where mod(x.rn,2) =1;