Detecting Numeric Only Strings via SQL/Oracle

I have the following select statement which is being used to calculate costs for equipment inventory data in an Oracle 7.2 database:

  SELECT "DC_LINE_CODING"."AMOUNT_FL"
    FROM "DC_LINE_CODING"
   WHERE To_Number(SubStr("DC_LINE_CODING"."GL_CODE_ID",1,5)) > 03999

The problem I have is with the WHERE clause. The GL Code Id is a 5 character
string which can contain alpha characters. I want to ignore these GL Code Ids
and only consider numeric-only GL Code Ids. There does not seem to be an Oracle
function which can deterimine this numeric-only status. Does anyone know of
another work-around ?

Thanks in advance. Chris Gatto Received on Fri Nov 22 1996 - 00:00:00 CET