If you want AB to GH, try this (Oracle tested):

```
with mydata as (
select 'A' mycol from dual
union all
select 'B' mycol from dual
union all
select 'C' mycol from dual
union all
select 'D' mycol from dual
union all
select 'E' mycol from dual
union all
select 'F' mycol from dual
union all
select 'G' mycol from dual
union all
select 'H' mycol from dual
)
select c1.mycol, c2.mycol
from mydata c1
cross join mydata c2
where c1.mycol < c2.mycol
order by c1.mycol, c2.mycol
/
```