[Q] Conditions in the column expression?

I have a table t with columns n and m of type VARCHAR. I want to retrieve the entire n column, but I want the entries to be ordered such that those entries where m is null come first. As pseudo-code:

    SELECT n, (IF m IS NULL THEN 0 ELSE 1) AS c     FROM t
    ORDER BY c, n;

Moreover, I want to retrieve all those entries of n whose length is greater than 5, but I want NULL values for all those entries whose length is less or equal than 5. In pseudo-code:

    SELECT (IF LENGTH(m) <= 5 THEN NULL ELSE m)     FROM t;

How do I do this in Oracle? Received on Wed Nov 26 2003 - 03:09:05 CST