Date:         Tue, 21 Jun 2011 11:54:20 -0400
Reply-To:     Tom Smith <need_sas_help@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Tom Smith <need_sas_help@YAHOO.COM>
Subject:      Re: A data manupulation Question
Comments: To: Ya Huang <ya.huang@AMYLIN.COM>

You are correct but also note that this problem is little more complicated
than any of you thought. plz find he two conditions below:

1) if variable "STDAT" is not missing then keep the observations where
   ----------------------------------
DATSTOP < STDAT.

Note: I think you both missed the part "if variable "STDAT" is not
missing". here only talig about "STDAT", NOT bother "STDAT" and "DATSTOP".

2)if variable "STDAT" or "STDAT" is missing then the observations remains.

Note: you are right any of them can be missing.

Please help me. I am cofussed. Also nmiss fuction is not working for me.
looks like I have a old sas version. Please make if compatable to old SAS.

Thank you so much from the bottom of my heart.