Re: Aliias names in select criteria

Bob,

which version of PostgreSQL do you use?

On Tue, 04 Jun 2002 12:49:35 -0400, "Bob Powell" <Bob@hotchkiss.org>
wrote:
>
>To whom it may concern:
>
>The following selection criteria causes my box to start a process that gives no result.
>
>SELECT P.Last_Name, P.First_Name, S.Status, S.Entry_Year, S.Graduation_Year, S.Former_School, S.Day_or_Board,
S.Admissions_Id,P.Participant_Id, P.Birthday, P.Modification_Date 
>FROM Participants P, Students S
>WHERE Participant.Participant_Id = Students.Participant_Id

With version 7.1.3, 7.2, 7.2.1, and 7.3devel (two or three week old) I
get the messages
    NOTICE:  Adding missing FROM-clause entry for table "Participant"
    NOTICE:  Adding missing FROM-clause entry for table "Students"

This means, the engine does a CROSS JOIN of P, S, Participant, and
Students restricted only by
    Participant.Participant_Id = Students.Participant_Id.
>
>It also throws the linux box into a process that has to be killed even though I've exited the client.

So if
 n1 = number of rows in Participant
 n2 = number of rows in Students
 n3 = number of rows in (Participant INNER JOIN Students
                         ON Participant.Participant_Id =
                            Students.Participant_Id),
you can expect to get a result set of n1 * n2 * n3 rows.

Servus
 Manfred