In addition to Cathy's solution, I sometimes find the following useful...

Example:
SELECT *, ;
SPACE(13) AS charfield1, ;
000.00 AS numfield2, ;
.F. AS logicfield3, ;
{ / / } AS datefield4 ;
FROM OldTable INTO NewTable

This will select all records, plus the new fields with blank templates, into a new table. The old table can then be deleted and the new table renamed.

Hope this helps,
Alan