Date:         Tue, 16 Mar 2004 13:07:30 -0500
Reply-To:     SASbum@AOL.COM
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Jimmy Greeley <SASbum@AOL.COM>
Subject:      Re: How does SAS deal with missing value of the ByVariable in
              merging
Content-Type: text/plain; charset=iso-8859-1

data one;
id=1; x=2; y=3; output;
id=2; x=3; y=4; output;
id=.; x=5; y=6; output;
id=.a; x=7; y=8; output;
id=.z; x=7; y=7; output;
run;
data two;
id=1; x=1; y=1; output;
id=2; x=1; y=1; output;
id=.; x=1; y=1; output;
id=.a; x=1; y=1; output;
id=.z; x=1; y=1; output;
run;
proc sort data=one; by id; run;
proc sort data=two; by id; run;
data new;
merge one two; by id; run;
proc print; run;


        Obs    id    x    y
         1      .    1    1
         2      A    1    1
         3      Z    1    1
         4      1    1    1
         5      2    1    1


In a message dated 3/10/2004 2:20:18 PM Eastern Standard Time, diskin.dennis@KENDLE.COM writes:

>
> Huong,
>
> When merging, SAS treats a missing value the same as any other value. This
> is the same as if you had program logic such as IF A EQ B. The result
> would be true when both are missing. This very different from the way SQL
> works in most database systems where a missing (NULL) can never equal
> anything.
>
> In other words, all the missing values in one dataset would match to all
> the missings in the other. Special missings are each distinct values when
> it comes to merging.
>
> HTH,
> Dennis Diskin
>
>
>
>
>
> 0101 htns <htns0101@YAHOO.COM>
> Sent by: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
> 03/10/2004 01:54 PM
> Please respond to 0101 htns
>
>
>        To:     SAS-L@LISTSERV.UGA.EDU
>        cc:
>        Subject:        How does SAS deal with missing value of the ByVariable in merging
>
>
> Dear SAS-Lers,
>
> Suppose I want to get all of the observations, which are in both data
> sets. The by variable has some missing values in both sets. Will these
> observations be in the output data set? How does SAS deal
> with this
> situation? Any response would be appreciated.
>
> Huong
>
>
>
>
> ---------------------------------
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