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

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.