select nvl(cc.maf,dd.maf) maf, dd.a, dd.b,cc.c from cc full outer join (select nvl(aa.maf,bb.maf) maf,a,b from aa full outer join bb on aa.maf=bb.maf) dd on cc.maf=dd.maf
select maf, (select A from AA where maf = CC.maf) as A, (select B from BB where maf = CC.maf) as B, C from CC order by C
dd.a,
dd.b,cc.c
from
cc
full outer join
(select nvl(aa.maf,bb.maf) maf,a,b from aa full outer join bb on aa.maf=bb.maf) dd
on cc.maf=dd.maf
(select A from AA where maf = CC.maf) as A,
(select B from BB where maf = CC.maf) as B,
C
from CC order by C