select * from aa left join bb on aa.b = bb.b
a b b1 d
1 1 1 3
2 2 2 4
3 3 NULL NULL
1 4 NULL NULL
2 5 NULL NULL
select * from aa left join bb on aa.b = bb.b where bb.d is not null
a b b1 d
1 1 1 3
2 2 2 4
select * from aa right join bb on aa.b = bb.b
a b b1 d
1 1 1 3
2 2 2 4
NULL NULL 11 11