USE tpch1;
select c2 from sub1 order by 1;
c2
NULL
1
1
2
3
99
select c2 from sub2 order by 1;
c2
NULL
1
2
2
3
4
5
select sub1.c2 as x, sub1.c2 as y from sub1, sub2 where sub1.c2 = sub2.c2 order by 1, 2;
x	y
1	1
1	1
2	2
2	2
3	3
select sub1.c2 as x, sub2.c2 as y, count(sub2.c2) as z from sub1, sub2 where sub1.c2 = sub2.c2 group by 1, 2 order by 1, 2;
x	y	z
1	1	2
2	2	2
3	3	1