All of you who responded drove home my need to explicitly enter null when there are no data for a column.
Thanks,
Rich
Just in case you miss this little nuance, you don't necessarily _have_ to specify a NULL for that column, depending how you're doing your inserts. You haven't show us your table or what INSERT you're using, but all of these examples will work, and don't specify an explicit NULL:
CREATE TEMP TABLE foo (a INTEGER NOT NULL, b INTEGER NOT NULL, c DATE);