Date:         Mon, 27 Aug 2007 15:16:10 -0000
Reply-To:     Haris <Karovaldas@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Haris <Karovaldas@GMAIL.COM>
Organization: http://groups.google.com
Subject:      How to count in sub-sets of a continuous variable?
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset="iso-8859-1"

I have a dataset with multiple rows per ID.  Each of the rows has a
unique time stamp.  I want to count how many ID's have data within
certain time windows.  Here's a code that counts the number of rows in
each time-window.

proc sql ;
        title 'N of Patients and Visits during FU by Procedure' ;
        select  count('CTU-ID'n)                         label='Total Visits',
                count (unique 'CTU-ID'n)                label='Total Patients',
                sum(Days LE 30)                         label='Visits within 30 Days',
                sum(Days between 31 and 90)      label='Visits 31 to 90 Days',
                sum(Days between 91 and 180)    label='Visits 91 to 180 Days',
                sum(Days between 181 and 270)   label='Visits 181 to 270 Days',
                sum(Days GT 270)                       label='Visits 270+ Days'
        from AFLee.Merged ;
quit ; title ;

How do I make it count not rows, but unique IDs within those windows?

Thanks.