with a(a,b,c) as (values
('2007-01-01', 1 ,1),
('2007-01-01', 1 ,2)),
b(a,b,c) as (values
('2007-01-01', 2, 1),
('2007-01-01', 2, 2),
('2007-01-01', 2, 3),
('2007-01-01', 2, 4),
('2007-01-01', 2, 5))

select a.a as a_a, a.b as a_b, a.c as a_c,
       b.a as b_a, b.b as b_b, b.c as b_c
  from b left join a on a.c=b.c;

A_A        A_B         A_C         B_A        B_B         B_C       
---------- ----------- ----------- ---------- ----------- -----------
2007-01-01           1           1 2007-01-01           2           1
2007-01-01           1           2 2007-01-01           2           2
-                    -           - 2007-01-01           2           3
-                    -           - 2007-01-01           2           4
-                    -           - 2007-01-01           2           5