At 12:40 PM 9/9/2002, you wrote:
>Hello,
>
>Without giving me the RTFM, and in 25 words or less...
>
>Can someone tell me what an index column is and does for a query?
>
>Thanks,
>
>Will
Will,
Without an index the entire table has to be read to find the
results of the query. Even simple queries like "select * from table where
acct=4" means it has to read the entire table. If your table only has a few
dozen records in it, then it won't matter if you have an index or not. But
if it had 10,000 records, an index will retrieve it about a thousand times
faster. Bear in mind that the more indexes you have, the slower the inserts
become because the index must be maintained. You will also use up more disk
space. So put only indexes on columns that will be used for heavy searching
or joins.
Mike
(Ok, I used more than 25 words, so sue me. :-)
---------------------------------------------------------------------
Before posting, please check:
http://www.mysql.com/manual.php (the manual)
http://lists.mysql.com/ (the list archive)
To request this thread, e-mail <[EMAIL PROTECTED]>
To unsubscribe, e-mail <[EMAIL PROTECTED]>
Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
