Mysql mysql_num_rows（$ result）; 备择方案

Question

Is there a quicker query of counting how many rows there are using a WHERE statement? The current query I use in PHP is:

$result = mysql_query("SELECT SQL_NO_CACHE id FROM users WHERE user = '$tnuser'");
$total = mysql_num_rows($result);

The table engine is InnoDB and ID is primary key and user is indexed. This query is ran 300+ a second so any performance gain would be good. The total count is always changing and users are deleted/added very often.

Thank you

Answer 1

Usually its faster to use the aggregate functions of SQL to count something. You could for example try

SELECT COUNT(*) FROM users WHERE user = '$tnuser'