Re: SQL question

I was lead to believe that the benefit of JOINing tables was that you could explicitly state the criteria to be used - and hence the 'index'.
So
SELECT a.blah
     FROM table1 AS a
               JOIN table2 AS b
                       JOIN table3 AS c
                       ON c.foreignRecNo = b.recNo
              ON b.foreignRecNo = a.recNo

explicitly says use the foreign key rec nos on table2 and table3 - where as

SELECT a.blah
    FROM table1 AS a, table2 AS b, table3 AS c
    WHERE b.foreignRecNo = a.recNo
    AND      c.foreignRecNo = b.recNo

would leave it up to the optimiser to decide the best route to the data.

Personally, since realising how JOIN works (and the JOIN syntax), I find that layout far easier to read as well - especially where you get convoluted where clauses such as:

WHERE table1.field1    = table3.field4
AND     table2.field10   = table4.field2
AND     table2.field7     = table4.field3
AND     table2.field5     = table5.field1
AND     table .....

where the 'joins' are on composite keys and the order of specification of the 'join' isn't necessarily intuitive.

On Tue, 2008-02-19 at 14:49 +1100, Phillip Smith wrote:

De: pgsql-novice-owner@postgresql.org
[mailto:pgsql-novice-owner@postgresql.org] En nombre de Mag Gam
Enviado el: Monday, February 18, 2008 5:37 PM
Para: pgsql-novice@postgresql.org
Asunto: [NOVICE] SQL question
 
>> Is it better to use "JOIN" or comma method with equal sign when doing
table joins?

-----Original Message-----
From: pgsql-novice-owner@postgresql.org
[mailto:pgsql-novice-owner@postgresql.org] On Behalf Of Cesar Alvarez
Sent: Tuesday, 19 February 2008 14:21
To: pgsql-novice@postgresql.org
Subject: Re: [NOVICE] SQL question

> It's better to use Join cause its easier to read the Sql statement


I'm guessing there might be some effect on the planner as well maybe...?
Someone smarter than me could shed some more light...


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