Rob,
First of all I would say, your query is pretty badly laid out. First,
unless you need every fields from a table returned only ask for those
specific fields, and do you have an index on the combination of person_id +
session_start? If not, your query will always be slow.
But this is how I would write it.
Select bla, bla2 from table
where person_id = 10
and session_start between ('2004-09-01 00:00:00' and '2004-10-01 00:00:00')
Then why would you order by session_start, when the odds are that you added
the data to the table by time anyway. So why waste the servers time
ordering something that may already be ordered for you automatically. But
you would know that better than any of us.
A query like this should take no longer than 0.1 seconds to execute in most
cases, even with a few gigs of data.
Doonny
> -----Original Message-----
> From: news [mailto:[EMAIL PROTECTED] On Behalf Of Rob Keeling
> Sent: Thursday, December 23, 2004 11:55 AM
> To: mysql@lists.mysql.com
> Subject: Optimising a query on a large table.
>
> I have a 152MB MyISAM table that I am trying to execute a simple select
> statement on,
> I need to retreave all rows with a given index, sorted by date.
>
> This is taking a very long period of time to execute.
>
> What can I do to speed up the query.
>
> The sql is,
>
> SELECT * FROM table WHERE (person_id LIKE 10) AND (session_start >
> '2004-09-01 00:00:00') AND (session_start < '2004-10-01 00:00:00') Order
> by
> session_start
>
> Thanks
>
> Rob Keeling
>
>
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