IF Select statement syntax issue

I am using SSIS and DB2. I have db2 query IF....Select query as follows:

if 'a'='a' then
select count(*) from x;
elseif 'b'='b'
select count(*)from y;
else
select count(*) from z;
end if

Somehow this is not working neither on db2 client nor on ssis. Can anyone suggest would could be wrong with this?

Thanks,
hs