Select Multiple Random Rows with MySQL PHP Benchmark

gistfile1.php

<?php
$max = 100;
$table = 'mytable';
$limit = $max;
$mysql = mysql_connect('localhost', 'root', '');
mysql_query('USE test'); 
?>
<h2>Order By Rand()</h2>
<?php
//  Start TIMER
$stimer = explode( ' ', microtime() );
$stimer = $stimer[1] + $stimer[0];
?>
<?php mysql_query("SELECT * FROM {$table} ORDER BY RAND() LIMIT {$limit}"); ?>
<?php
//  End TIMER
$etimer = explode( ' ', microtime() );
$etimer = $etimer[1] + $etimer[0];
echo '<p>';
printf( "Execution Time: <b>%f</b> seconds.", ($etimer-$stimer) );
echo '</p>';
?>
<p>&nbsp;</p>
<h2>Order By Rand() Alternative</h2>
<?php
//  Start TIMER
$stimer = explode( ' ', microtime() );
$stimer = $stimer[1] + $stimer[0];
?>
<?php mysql_query("SELECT * FROM {$table} WHERE RAND()<(SELECT (({$limit} / COUNT(*)) * 10) FROM {$table}) ORDER BY RAND() LIMIT {$limit}"); ?>
<?php
//  End TIMER
$etimer = explode( ' ', microtime() );
$etimer = $etimer[1] + $etimer[0];
echo '<p>';
printf( "Execution Time: <b>%f</b> seconds.", ($etimer-$stimer) );
echo '</p>';
?>
<p>&nbsp;</p>
<h2>Inner Join</h2>
<?php
//  Start TIMER
$stimer = explode( ' ', microtime() );
$stimer = $stimer[1] + $stimer[0];
?>
<?php for($x=0; $x<$max; $x++){ ?>
<?php mysql_query("SELECT t1.* FROM {$table} AS t1 JOIN (SELECT ROUND(RAND() * (SELECT MAX(id) FROM {$table})) AS id) AS t2 WHERE t1.id >= t2.id LIMIT 1"); ?>
<?php } ?>
<?php
//  End TIMER
$etimer = explode( ' ', microtime() );
$etimer = $etimer[1] + $etimer[0];
echo '<p>';
printf( "Execution Time: <b>%f</b> seconds.", ($etimer-$stimer) );
echo '</p>';
?>
<p>&nbsp;</p>
<h2>User Variable</h2>
<?php
//  Start TIMER
$stimer = explode( ' ', microtime() );
$stimer = $stimer[1] + $stimer[0];
?>
<?php mysql_query("SELECT t.* FROM (SELECT ROUND(RAND() * (SELECT MAX(id) FROM {$table})) num, @num:=@num+1 FROM (SELECT @num:=0) AS a, {$table} LIMIT {$limit}) AS b, {$table} AS t WHERE b.num = t.id"); ?>
<?php
//  End TIMER
$etimer = explode( ' ', microtime() );
$etimer = $etimer[1] + $etimer[0];
echo '<p>';
printf( "Execution Time: <b>%f</b> seconds.", ($etimer-$stimer) );
echo '</p>';
?>