Você pode usar a técnica de Aketi Jyuuzou chamada Tabibitosan aqui:
SQL> create table mytable (id,chequeno)
2 as
3 select 1, 15 from dual union all
4 select 2, 19 from dual union all
5 select 3, 20 from dual union all
6 select 4, 35 from dual union all
7 select 5, 16 from dual
8 /
Table created.
SQL> with tabibitosan as
2 ( select chequeno
3 , chequeno - row_number() over (order by chequeno) grp
4 from mytable
5 )
6 select row_number() over (order by grp) "row"
7 , min(chequeno) "from"
8 , max(chequeno) "to"
9 from tabibitosan
10 group by grp
11 /
row from to
---------- ---------- ----------
1 15 16
2 19 20
3 35 35
3 rows selected.
Atenciosamente,
Rob.
