Robert Cummings wrote:
On Wed, 2007-10-03 at 14:49 -0700, Jim Lucas wrote:
This is only from my own personal testing. Mind you that I have only been using PostgreSQL for a
year or so. But one problem that I have always ran into with MySQL is that when JOIN'ing tables
that have large data sets is a PITA.
Were you doing left joins when you experienced those problems? Left
joins are usually very fast.
So, if I was running MySQL, I would use SQL #1, but if I were using PostgreSQL,
I would use SQL #2
I'd use the left join whenever available.
Cheers,
Rob.
Honestly, I cannot remember. It was right when I first started with
PHP/mysql back in 1999. I think we were using a JOIN (without the LEFT)
Which I think the default is an INNER JOIN if I do recall.
I really have never played with performance over the past few years.
This past year I have been working on a new DB with Call Detail Records
for a phone company. On average we have to deal with processing 2 - 4
million records each billing cycle. So, having to work with that amount
of CDR's and a couple thousand client records that are associated with
them, makes for a good performance test on SQL statements.
--
Jim Lucas
"Perseverance is not a long race;
it is many short races one after the other"
Walter Elliot
"Some men are born to greatness, some achieve greatness,
and some have greatness thrust upon them."
Twelfth Night, Act II, Scene V
by William Shakespeare
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