[thelist] new & improved SQL join syntax?
Sarah Adams
mr.sanders at geekjock.ca
Fri Jan 19 08:03:12 CST 2007
I regularly read Rudy Limeback's "Ask the Expert" column (it's
fantastic, BTW, I highly recommend it for anyone who writes SQL on a
regular basis). In Wednesday's column he mentioned that the SQL join
syntax I've always used (i.e. a comma-separated list of tables, followed
by one or more WHERE clauses) is outdated. He's mentioned this
previously, but I didn't take it too seriously till I read it again today.
"Please always try to write your joins using JOIN syntax, not the older
style which lists tables using commas."
http://searchoracle.techtarget.com/expert/KnowledgebaseAnswer/0,289625,sid41_gci1239517,00.html
So he's suggesting this syntax is outdated:
SELECT a.foo, a.field1, b.qux, b.field2
FROM table1 as a, table2 as b
WHERE a.field1 = b.field2
and should be replaced with:
SELECT a.foo, a.field1, b.qux, b.field2
FROM table1 as a
INNER JOIN table2 as b
ON a.field1 = b.field2
Has anyone else heard this, and can they shed any light on it? I guess
I'm just wondering where this change came from, how important it is, do
I need to go back and re-work countless queries to use this syntax, etc?
Also, if anyone has an easy-to-understand tutorial on JOIN clauses
(especially LEFT JOIN and the like), I'd really appreciate it - it's one
of those things that I understand but couldn't for the life of me
explain to someone else :)
--
sarah adams
web developer & programmer
portfolio: http://sarah.designshift.com
blog: http://hardedge.ca
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