Joined: 27 Oct 2009 Posts: 2429 Location: Netherlands, Amstelveen
Its all in the reference manual :
IF fieldname [NOT] NUMERIC
NUMERIC tests for the digits 0 through 9 (in the correct format for the field's data type), and for a possible algebraic sign in the low-order position of type P fields or in the high-order position of type N fields.
IF fieldname [NOT] ALPHABETIC
ALPHABETIC tests for the characters A through Z or a blank space in each byte of the subject field.