LISTSERV at the University of Georgia
Menubar Imagemap
Home Browse Manage Request Manuals Register
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (January 2003, week 5)Back to main SAS-L pageJoin or leave SAS-L (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Thu, 30 Jan 2003 18:55:30 +0100
Reply-To:     Peter Crawford <peter.crawford@DB.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter Crawford <peter.crawford@DB.COM>
Subject:      Re: Equivalent of NODUPKEY in PROQ SQL
Content-type: text/plain; charset=iso-8859-1

as put by Master-Ian Whitlock

"It is unclear to me whether you are complaining about the design PROC SORT or how data is managed where you work."

I have nothing to complain about in proc sort.

NOdupKey works exactly as documented

That I consider this to cause uncontrolled loss of information, reflects the way I see it used, and no more.

Appreciate Ian's sympathy

Peter

Datum: 30/01/2003 17:33 An: SAS-L@LISTSERV.UGA.EDU

Antwort an: Ian Whitlock <WHITLOI1@WESTAT.COM>

Betreff: Re: Equivalent of NODUPKEY in PROQ SQL Nachrichtentext:

Peter,

You originally wrote in part:

> The use of "procs sort nodupkey" I consider as an indicator > of weak analysis and design.

and then from the message below:

> (I think a better data management approach would be to > lose or drop _all_ those uncontrolled satelite variables).

It is unclear to me whether you are complaining about the design PROC SORT or how data is managed where you work.

If the former I would translate your parenthetical remark as

The problem with PROC SORT is that it doesn't care about the variables that you don't care about.

If the latter then I sympathize with you but find nothing wrong with PROC SORT except for the misleading NODUP option.

IanWhitlock@westat.com -----Original Message----- From: Peter Crawford [mailto:peter.crawford@DB.COM] Sent: Thursday, January 30, 2003 9:43 AM To: SAS-L@LISTSERV.UGA.EDU Subject: Re: Equivalent of NODUPKEY in PROQ SQL

Hi Paul the "uncontrolled way" to which I refer, occurs (too often) in the common enough (around here) resolution of an m:n merge.

The part I consider "uncontrolled" is implied "If there is no change in the sort keys, the record is not used" as in all the descriptions I have read about NOdupKey as in onLineDOc NODUPKEY checks for and eliminates observations with duplicate BY values. If you specify this option, PROC SORT compares all BY values for each observation to those for the previous observation written to the output data set. If an exact match is found, the observation is not written to the output data set.

Therefore, only the first observation of a group having the same key values is sorted. Even with the Equals option, we control only that it would be the first instance in the input data that would be used, but I consider that a weak level of control. (I think a better data management approach would be to lose or drop _all_ those uncontrolled satelite variables).

Without pre-processing, we cannot know how the non- key variables would compare. Of course, if pre-processing is available, the NOdupKey option, would probably be unneccessary

Kind Regards Peter Crawford

<snip>

--

Diese E-Mail enthält vertrauliche und/oder rechtlich geschützte Informationen. Wenn Sie nicht der richtige Adressat sind oder diese E-Mail irrtümlich erhalten haben, informieren Sie bitte sofort den Absender und vernichten Sie diese Mail. Das unerlaubte Kopieren sowie die unbefugte Weitergabe dieser Mail ist nicht gestattet.

This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.


Back to: Top of message | Previous page | Main SAS-L page