Select Random Records with Group By?

Question

Hi,
I currently select random records by using this type of SQL:
(SELECT *
FROM ( SELECT *
FROM ( SELECT *
FROM TABLEA
ORDER BY dbms_random.value
WHERE ROWNUM <= 100
Based on the following data, I now want to still pick out random records but I only want 1 record from the same ID and START_DATE but where the FLAG could be Y or N.
So with grouping by ID and START_DATE, I need to still be able to choose the record if it has anything from 1 entry or 10 entries per ID and START_DATE.
Could this be performed with a GROUP BY?
ID START_DATE FLAG
1 12/12/2005 Y
1 12/12/2005 N
1 12/12/2005 N
1 30/12/2005 Y
1 30/12/2005 N
1 30/12/2005 N
2 10/10/2005 Y
2 07/07/2005 Y
Thanks for any help.
Daniel

Answer 1

Try this [not tested]:
SELECT *
     FROM
          (SELECT *
               FROM
               ( SELECT
                          ID
                         ,START_DATE
                         ,FLAG
                         ,ROW_NUMBER() OVER
                              (PARTITION BY ID,START_DATE ORDER BY dbms_random.value) RN
                    FROM TABLEA
               ORDER BY dbms_random.value
     WHERE RN = 1
          AND ROWNUM <= 100
     ;