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.


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

PHP Database Mailing List (
To unsubscribe, visit:

Reply via email to