select * from (select * from ${basictb}_event where ttype='1' and isopen='Y' and sdate<='$nowdate' and edate>='$nowdate' order by sdate desc) as a

union

select * from (select * from ${basictb}_event where ttype='1' and isopen='Y' and edate<'$nowdate' order by sdate desc) as b

서브쿼리로 한번 감싸서 합쳐주니 원래 의도했던 순서대로 나온다...

union order by