Reduce Number of mysql_query()

[perky416]

Hi guys,

 

Yesterday i was told that the more mysql_query()'s i have the more my website will slow down to a halt if it get a large number of visitors. My website has LOADS of mysql_query()'s.

 

Most of my queries are select queries with he odd update and insert query. I tried reading up on how to combine multiple select queries on a page into 1, however someone on another forum said you cannot combine multiple queries using mysql_query(). If this is not possible please could somebody tell me how i would go about reducing the number of selects?

 

Thanks.

[Zane]

It depends really on what your queries look like.  If you notice, at the bottom of this page it says

Page created in 0.024 seconds with 16 queries.

and believe me, those queries are long.

[floridaflatlander]

What do you call large?

 

I also don't know what you mean by combine queries but basiclly you can write and/or place your queries so you can use the data again if needed.

 

I'm sure the guys in the know on here will want to see some table structure(s) and queries to give you details.

 

 

[perky416]

Oh yeah i never noticed that before. That totally contradicts what I read somewhere as someone said its best to have 1 query per page, maximum of 4 if its a complex page.

 

These are a few of the select queries on one of my pages. I know i should replace * with the actual file names i need. I found out that i should do this after i wrote the page. I only have 5 select queries on this page however on one page i have about 30.

 

$query = mysql_query("SELECT * FROM users WHERE id='$id'");
$payment_query = mysql_query("SELECT * FROM payment_info WHERE username='$username'");
if (mysql_num_rows(mysql_query("SELECT email FROM users WHERE email='$email'")) > 0)

 

On the page that has 30 queries, most of them are in if statements, so only about 5 will be used at any 1 time. Im not too sure if this will make a difference or not.

 

Thanks

[Zane]

Select everything you can from one table.  If you repeat a select for one value of the same table then you're not doing it right.

 

In other words... your code is redundant.  You could have easily checked the email value after you selected * from users in the beginning.

[perky416]

Good advice! Looking at it like that with them next to each other I see what you mean.

Would using a different query for each different table should be ok? I only have about 12 tables, and only about 3 of them are used on any 1 page.

 

Thanks

[Zane]

So long as the query has the information you want, then yea.. use one query per table.  Though if you start limiting your queries with WHERE and LIMIT clauses you're least likely to have that information.  I'm not saying don't use WHERE and LIMIT, I'm saying.. don't waste valuable data and then recreate it.

[perky416]

Ok thanks mate,

 

Ill try and make better use of my queries.

 

Thanks