Date:         Fri, 20 Sep 1996 18:10:54 +0100
Reply-To:     John Whittington <johnw@MAG-NET.CO.UK>
Sender:       "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From:         John Whittington <johnw@MAG-NET.CO.UK>
Subject:      Re: deleting (groveling apology)
Comments: To: "Zuckier, Gerald" <Zuckier@CHIME.ORG>

On Thu, 19 Sep 1996, "Zuckier, Gerald" <Zuckier@CHIME.ORG> wrote:
 
>Minor quibble: isn't it going to take the same amount of time for SQL to
>do the same task, as it will have an implied sort?
 
This is an oft-debated point - and I don't claim to have the slightest
understanding of the actual internal implementation of SQL.  However, my
personal experience is that, particularly with large datasets, these
'implied sorts' (which presumably must be there, at least 'functionally')
are probably *slower* than explicit sorts accompanied by DATA step code -
hence the comment in my last message that Thomas's method (using explicit
sorts) could well be the more efficient.
 
>Infinitesimal quibble: you don't need to use the var in the by statement
>do you, although it must be sorted by?
 
Yes, I agree on both counts - that this is true, and that it is an
'infinitesimal' quibble :-)
 
Regards,
 
John
 
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