Date:         Wed, 15 Oct 2008 17:11:55 -0400
Reply-To:     "Howard Schreier <hs AT dc-sug DOT org>"
              <schreier.junk.mail@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Howard Schreier <hs AT dc-sug DOT org>"
              <schreier.junk.mail@GMAIL.COM>
Subject:      Re: MS Access missing values not picked up with "WHERE ... LE 0"

On Wed, 15 Oct 2008 12:55:37 -0700, Tom Frenkel <frethoa@AOL.COM> wrote:

>To comp.soft-sys.sas --
>
>I'm reading a MS Access table, using a LIBNAME statement to assign the
>libref ACC.  There is a "Date/Time" field called EndDate that contains
>missing values.  I'm trying to print the observations with a missing
>value, or zero, in the field ENDDATE.  When I write
>
>        proc print data=acc.StudentInstructors ;
>        where enddate LE 0 ;
>
>no observations with missing values of ENDDATE are printed!  However,
>when I write
>
>        proc print data=acc.StudentInstructors ;
>        where (enddate = . ) or (enddate = 0) ;
>
>the observations with missing values of ENDDATE are, correctly,
>printed.
>
>Can anyone explain this odd behavior?  I'm using SAS 9.1, on Windows
>XP. Thanks much!
>
>         --Tom

See
http://www.sascommunity.org/wiki/Be_Aware_of_Implicit_Pass-Through