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Date:         Thu, 12 Jun 2008 17:53:35 -0400
Reply-To:     "Howard Schreier <hs AT dc-sug DOT org>"
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Howard Schreier <hs AT dc-sug DOT org>"
Subject:      Re: Question on proc sql

On Thu, 12 Jun 2008 10:40:22 -0400, Sigurd Hermansen <HERMANS1@WESTAT.COM> wrote:

>Lorna: >I've just found a few free minutes to respond to your question about SAS >SQL ... > >You can trust me, the original SQLHead on SAS-L,

Are you sure? I started posting SQL solutions on SAS-L in about 1991.

>to give you an unbiased >and objective appraisal of SAS SQL's virtues vs. that other dirty Data >step quasi-procedural language that SAS still supports. Just replace >"Mac" with "SQL" and "PC" with "Data step" in those TV commercials and >you'll have the drift of my idea about SAS SQL vs. the SAS Data step >language. > >SQL currently dominates the arena of database programming languages. >That doesn't make SQL an ideal instance of a logic-set language, but it >has substantial advantages in some respects over languages that process >records and fields (or even those that process obs and variables). To >name a few, > >1. SQL operates on relations (views, tables, etc.), thus freeing >database programmers from the risky business of building explicit loops, >while Data steps allow a confusing mixture of step-by-step processes >(e.g., a sequence of assignments) and before and after operations (e.g., >ATTRIBUTE and KEEP statements); >2. A SQL SELECT statement always produces (yields) a relation, allowing >nesting of encapsulated SQL statements, while Data steps accumulate a >trail of datasets or views; >3. SQL allows references to a dataset/view and variable, making it >easier to figure out sources of values, while DATA steps don't; >4. SQL doesn't require a programmer to sort datasets and remains >agnostic to ordering of tuples (obs) and attributes (variables), unlike >the Data step; >5. SQL joins appear several levels higher on the database programming >tree of evolution than Data step merges (think sea otter vs. alligator); >6. SAS SQL segues cleanly into SAS/Access to external databases; >7. SAS SQL programmers have more fun. > >Now I must add that SAS-L has a number of very clever and creative >programmers who make good use of the Turing-complete features of the SAS >Data step. They may see some of what I see as disadvantages of the Data >step as advantages. It pays to learn both, and to continue learning >both. Really good programmers don't use the same set of Data step or SQL >operations in the same way that they used them a few years earlier. >S > >-----Original Message----- >From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of >Simon, Lorna >Sent: Monday, June 09, 2008 10:36 AM >To: SAS-L@LISTSERV.UGA.EDU >Subject: Question on proc sql > > >I have a question about sql - what is the advantage of learning it? Are >there things you can do in sql that you can't do in a regular sas data >step?

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