Query for matrix table

Question

Hello,
Is it possible to make a query thats create a matrix table.
select * from TCOLUMN
ID NAME
== ====
1 A
2 B
select * from TROW
ID NAME
== ====
1 X
2 Y
select * from TMATRIX
TCOLUMN_ID TROW_ID VAL
========== ======== ==
1 1 k
1 2 m
2 1 l
2 2 n
The query have to display:
null X Y
A k m
B l n
Thanks.

Answer 1

Like this?
SQL> column name format a4 heading "null"
SQL> column x format a4 heading "X"
SQL> column y format a4 heading "Y"
SQL> create table tcolumn
  2  as
  3  select 1 id, 'A' name from dual union all
  4  select 2, 'B' from dual
  5  /
Tabel is aangemaakt.
SQL> create table trow
  2  as
  3  select 1 id, 'X' name from dual union all
  4  select 2, 'Y' from dual
  5  /
Tabel is aangemaakt.
SQL> create table tmatrix
  2  as
  3  select 1 tcolumn_id, 1 trow_id, 'k' val from dual union all
  4  select 1, 2, 'm' from dual union all
  5  select 2, 1, 'l' from dual union all
  6  select 2, 2, 'n' from dual
  7  /
Tabel is aangemaakt.
SQL> select c.name
  2       , max(decode(r.name,'X',m.val)) x
  3       , max(decode(r.name,'Y',m.val)) y
  4    from tmatrix m
  5       , tcolumn c
  6       , trow r
  7   where m.tcolumn_id = c.id
  8     and m.trow_id = r.id
  9   group by c.name
10  /
null X    Y
A    k    m
B    l    n
2 rijen zijn geselecteerd.Groet,
Rob.