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

Roy,

can record_status be null? if so null will neither equal 'A' nor not equal 'A'.

If record_status can be null try count(*) .... where record_status is null;

Rod Corderey
Lane Associates
Lane_Associates_at_Compuserve.com
http://www.Lane-Associates.com

Roy Smith wrote:
>
> 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 - 15:57:14 CDT