Convert 1 row, multiple (identical) columns into 1 column, multiple rows

Question

I have 10g, so unpivot is unavailable to me. I have a query that looks like:
with data as (
select 1,2,3 from dual
) select * from data
which returns 1,2,3. I need it to return:
1
2
3 and be able to name the output column. The results of this will be used in a sub-select in an IN clause. This is a trivial example. In reality the list of numbers will be varied and large - too many to either use bind variables or to put in the IN clause as a list. Is there a simple way I'm overlooking?

Answer 1

Hi,
One way to unpivot is to join to a table that has as many rows as you need. Instead of an actual table, you can always generate a Counter Table (actually a result set), with exactly the right number of rows. Use CASE (or something similar) go get a different column for each row of the counter table.
For example, to get the 3 columns of the scott.dept table onto 3 separate rows:
WITH     cntr     AS
     SELECT     LEVEL     AS n
     FROM     dual
     CONNECT BY     LEVEL <= 3
SELECT     CASE     c.n
         WHEN  1  THEN  TO_CHAR (d.deptno)
         WHEN  2  THEN  d.dname
         WHEN  3  THEN  d.loc
     END      AS data
FROM          scott.dept     d
CROSS JOIN     cntr          c
;Output:
DATA
10
20
30
40
ACCOUNTING
RESEARCH
SALES
OPERATIONS
NEW YORK
DALLAS
CHICAGO
BOSTON