Add rows to query result?

Question

Is it possible to add rows to a SQL query's result, similar to the COMPUTE command in SQL*Plus?
That is, for example, when the value for column A changes, add a row after the previous row (the last one before column A changed) to show the sum of the values of column B.
e.g.
<PRE>A B
1 3
1 4
1 5
12
2 9
2 -1
2 -7
1</PRE>

Answer 1

SQL> create table sales (person,city,sales)
  2  as
  3  select 'Alice', 'Phoenix', 19 from dual union all
  4  select 'Alice', 'Tulsa', 11 from dual union all
  5  select 'Bob', 'Phoenix', 17 from dual union all
  6  select 'Bob', 'Tulsa', 9 from dual union all
  7  select 'Tony', 'Miami', 5 from dual union all
  8  select 'Tony', 'San Francisco', 4 from dual union all
  9  select 'Tony', 'San Francisco', 3 from dual
10  /
Tabel is aangemaakt.
SQL> select case grouping_id(person,city,rowid)
  2         when 1 then 'Sub-Total for'
  3         when 3 then 'Sub-Total for'
  4         when 7 then 'Grand Total'
  5         end notes
  6       , person
  7       , city
  8       , sum(sales) sales
  9    from sales
10   group by rollup(person,city,rowid)
11  having grouping_id(city,rowid) != 1
12      or count(*) > 1
13   order by person
14       , city
15       , grouping(rowid)
16  /
NOTES         PERSO CITY               SALES
              Alice Phoenix               19
              Alice Tulsa                 11
Sub-Total for Alice                       30
              Bob   Phoenix               17
              Bob   Tulsa                  9
Sub-Total for Bob                         26
              Tony  Miami                  5
              Tony  San Francisco          4
              Tony  San Francisco          3
Sub-Total for Tony  San Francisco          7
Sub-Total for Tony                        12
Grand Total                               68
12 rijen zijn geselecteerd.Regards,
Rob.