Date:         Wed, 22 Jun 2011 03:55:07 -0400
Reply-To:     Jim Groeneveld <jim.1stat@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Jim Groeneveld <jim.1stat@YAHOO.COM>
Subject:      Re: A Data manupulation question

Hi Mahaesh,

(Signal=2) is a conditional expression yielding either 0 or 1, depending
on whether Signal=2 (true=1) or not (false=0). The SUM function sums its
arguments (ignoring missings). In this case there is only one argument, so
the condition might also have been [(Signal=2)=0] or [(NOT (Signal=2))] or
[(Signal ^= 2)]. All records where Signal=2 are discarded (not selected).

Regards - Jim.
--
Jim Groeneveld, Netherlands
Statistician/SAS consultant
http://jim.groeneveld.eu.tf


On Wed, 22 Jun 2011 02:55:22 -0400, Mahesh Kumar Peesari
<peesari.mahesh@GMAIL.COM> wrote:

>Hi zhangyu,
>
>Can you please tell what sum(signal=2)=0 is doing ,
>Is it flagging,if so how is it doing ,can you please explain.
>
>proc sql;
>create table want as
> select *  from have
>   group by subject;
>    having sum(signal=2)=0;
>quit;
>
>Thanks,
>Mahaesh P