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

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?

SQL> select count(*) from phone;

  COUNT(*)

     13042

SQL> select count(*) from phone where record_status = 'A';

  COUNT(*)

     12983

SQL> select count(*) from phone where record_status != 'A';

  COUNT(*)

         0

--
Roy Smith <roy_at_popmail.med.nyu.edu>
New York University School of Medicine Received on Tue May 05 1998 - 10:18:41 CDT