pdo_select

<?php
$mtime = explode(' ', microtime());
$tstart = $mtime[1] + $mtime[0];
//////////////////////////////////

try {
    $dbh = new PDO('mysql:host=localhost;dbname=mysql', 'miha', 'qwerty');
}
catch(PDOException $e) {
    echo $e->getMessage();
}

for ($i = 0; $i < 1000; $i++)
{
    $sth = $dbh->prepare("SELECT * FROM help_relation WHERE help_keyword_id = :id");
    $sth->bindParam(":id", $u);
    $u = $i;
    $sth->execute();
    echo 'rowCount: '.$sth->rowCount().'<br>';
}

//////////////////////////////////
$mtime = explode(' ', microtime());
$mtime = $mtime[1] + $mtime[0];
echo '<br><br>Time: '.round((($mtime - $tstart) * 1000), 4).' мс<br>';
?>