SQL query, generating several rows by a value in a field

Question

I am using Oracle database. Imaging I have a table with a row as following
     col1  |  col2  | col3
    'Str1' | 'Str2' | 4
The value from col3=4 should generate 4 rows as following:
     col1  |  col2  | col3
    'Str1' | 'Str2' | 1
    'Str1' | 'Str2' | 2
    'Str1' | 'Str2' | 3
    'Str1' | 'Str2' | 4
After several hours in front of the screen and stil no luck - how can I create such a select query???

Answer 1

You're mixing up the 'standard' WITH clause and Recursive Subquery Factoring (which NEEDS a UNION ALL)  (see: http://docs.oracle.com/cd/E11882_01/server.112/e26088/statements_10002.htm#i2129904).
This should work on 10.2:
SQL> select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
SQL> with t as (select 'str1' col1, 'str2' col2, 4 col3 from dual
  2            )
  3  select col1
  4  ,      col2
  5  ,      level col3
  6  from   t
  7  connect by level <= col3;
COL1 COL2       COL3
str1 str2          1
str1 str2          2
str1 str2          3
str1 str2          4
See here as well: http://technology.amis.nl/2009/09/01/oracle-rdbms-11gr2-goodbye-connect-by-or-the-end-of-hierarchical-querying-as-we-know-it/