Date:         Fri, 25 Feb 2005 04:21:33 +0000
Reply-To:     toby dunn <tobydunn@HOTMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         toby dunn <tobydunn@HOTMAIL.COM>
Subject:      Re: Don't Believe Everything You Read
Comments: To: nospam@HOWLES.COM
In-Reply-To:  <200502250400.j1P40cBF031398@listserv.cc.uga.edu>
Content-Type: text/plain; format=flowed

Intersting how can a value of zero be a null value?  Very confused now?????



Toby Dunn




From: "Howard Schreier <hs AT dc-sug DOT org>" <nospam@HOWLES.COM>
Reply-To: "Howard Schreier <hs AT dc-sug DOT org>" <nospam@HOWLES.COM>
To: SAS-L@LISTSERV.UGA.EDU
Subject: Don't Believe Everything You Read
Date: Thu, 24 Feb 2005 22:52:32 -0500

The online doc (SAS SQL Procedure User's Guide) says that "to be compatible
with the rest of SAS, PROC SQL treats missing values the same as blanks or
zero values, and considers all three to be null values".

(http://support.sas.com/onlinedoc/913/getDoc/en/sqlproc.hlp/a001409512.htm)

On the numeric side, that of course mischaracterizes the "rest of" SAS, and
is not true.

Demonstration:

    data test;
    do value = 1,0,.,-1; output; end;
    run;

    proc sql;
    select case when value is null then put(value,2.) || ' is null.'
                else                    put(value,2.) || ' is not null.'
                end
     from test;
    quit;

This yields:

     1 is not null.
     0 is not null.
     . is null.
    -1 is not null.