Re: Either it's equal or it isn't, right?

record_status is NULL.

NULL does not fit into the normal sense of equality, because it is supposed to indicate an absence of a value rather than any particular value. count(record_status) should return the number of records for which record_status is not null, which by your queries should be 12983.

regards
-dave

Roy Smith <roy_at_popmail.med.nyu.edu> wrote in article <roy-0505981118410001_at_qwerky.med.nyu.edu>...
> I'm really stumped by the following three queries. The first says there
> are N1 records in the table. The second says N2 of them have a given
> value. Therefore, shouldn't the number of records which don't have the
> value be equal to N1-N2? Either record_status is 'A' or it isn't 'A'.
> What other possibilities exist?

   . . . Received on Tue May 05 1998 - 13:34:47 CDT