select only data with numbers from alphanumeric field

the field is VARCHAR2(20)

first four are letters
next 7 could be a mixture of letters/numbers

(most data in this column is 11 chars wide, some are more)

what I want to do is create a query like this:

select columnname from tablename

where columnname LIKE 'ABCD______#';
---------------------------^^^^^^ (6 spaces)------

so, the first four would be a specific letter sequence, the next 6 could be whatever,
and the last "thing" would be a number.

Thank you very much... Received on Wed Oct 16 2002 - 10:39:21 CDT