create table t1 (c1 int, c2 int, c3 int);
insert into t1 values (1,2,3),(4,5,6);
create table t2 (c1 int, c2 int, c3 int);
insert into t2 values (7,8,9),(10,11,12);
create table t3 (c1 int, c2 int, c3 int);
insert into t3 values (10,11,12),(13,14,15);
select * from
(
select ic1, ic2, ic3 from
(
select c1, c2, c3 from t1
) dt2 (ic1, ic2, ic3)
) dt1 (oc1, oc2, oc3)
join t2 on t2.c1 = dt1.oc1+6;