MYSQL Best Row Count Method - Large Database

Question

I have a MySQL database that contains over 400,000 rows. For my web based script, I have a page function. One of the steps to determine how many pages there should be is returning the number of rows in the table.

Let's pretend the table name is data .

I'm wondering what is the most efficient method to ONLY return the number of rows in the database.

I could obviously do something like:

$getRows = mysql_query("SELECT id FROM `data`") or die(mysql_error());
$rows = mysql_num_rows($getRows);

So that it only selects the id. But still, that will be selecting 400,000 + ID's worth of data and storing it on the stack (i think?) and seems less efficient as using a method such as finding the table status. I'm just not 100% sure how to use the table status method.

Feedback & opinions would be awesome. Thanks guys!

Answer 1

use count

SELECT count(id) FROM data

See this question for more info on getting counts. Make sure your id has an index in your table.

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Now, to find the number of unique rows, you can do

SELECT count(distinct(id)) FROM data

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alternatively, if you want to find the highest ID number (if you ID are autoincremental and unique) you can try SELECT max(id) FROM data to return the highest ID number present.

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I'd highly recommend this site to learn these basic functions: http://sqlzoo.net/

Answer 2

400,000 rows is not a lot at all. Keep it simple and just do:

select count(*) 
from `data`