How to create a Cross Tab view

Question

hi all
I have a table with records with this format:
Year, Month, Id, Value
2006, 01, 1, 10
2006, 02, 1, 15
2006 03, 1, 5
2006, 01, 2, 6
2008, 05, 1, 8
What I need to do is a view that will select these records for a specific year and show a column per month and a total column for the whole year. Rows will be by ID and every cell will show values
how can I do that?

Answer 1

Something like...
SQL> with t as (select 2006 as yr, 1 as mnth, 1 as id, 10 as val, 5 as daysusage from dual union all
  2             select 2006, 2, 1, 15, 2 from dual union all
  3             select 2006, 3, 1, 20, 1 from dual union all
  4             select 2006, 4, 1, 2, 1 from dual union all
  5             select 2007, 1, 1, 11, 7 from dual union all
  6             select 2007, 2, 1, 10, 7 from dual union all
  7             select 2007, 3, 1, 22, 6 from dual union all
  8             select 2007, 4, 1, 20, 10 from dual)
  9  -- ### END OF TEST DATA ###
10  select yr, id
11        ,max(decode(mnth, 1, val)) as m1_val
12        ,max(decode(mnth, 1, daysusage)) as m1_days
13        ,max(decode(mnth, 2, val)) as m2_val
14        ,max(decode(mnth, 2, daysusage)) as m2_days
15        ,max(decode(mnth, 3, val)) as m3_val
16        ,max(decode(mnth, 3, daysusage)) as m3_days
17        ,max(decode(mnth, 4, val)) as m4_val
18        ,max(decode(mnth, 4, daysusage)) as m4_days
19        ,sum(daysusage) as total
20  from t
21  group by yr, id
22  order by yr, id
23  /
        YR         ID     M1_VAL    M1_DAYS     M2_VAL    M2_DAYS     M3_VAL    M3_DAYS     M4_VAL    M4_DAYS      TOTAL
      2006          1         10          5         15          2         20          1          2       1             9
      2007          1         11          7         10          7         22          6         20      10            30
SQL>