Numeric in a char field validation???

All Informix guru, Anyone know if there is any SQL function that able validate that a 7-character defined field if having only numbers (0-9). Since we have a table column used as a charged ammount. Here is my current SQL query: "select sum(case when amount[1,7] not matches '[0-9][0-9][0-9][0-9][0-9][0-9][0-9]' then '0' else amount end +0)" Any help is appreciate. TN. --------------------------------------------------- Get free personalized email at http://www.iname.com