I need to count the number of rows from different(!) tables and save the results for some kind of statistic. The script is quite simple and working as expected, but I'm wondering if it's better to use a single query with (in this case) 8 subqueries, or if I should use separate 8 queries or if there's even a better, faster and more advanced solution...

I'm using MySQLi with prepared statements, so the single query could look like this:

$sql = 'SELECT
            (SELECT COUNT(cat1_id) FROM `cat1`),
            (SELECT COUNT(cat2_id) FROM `cat2`),
            (SELECT COUNT(cat2_id) FROM `cat2` WHERE `date` >= DATE(NOW())),
            (SELECT COUNT(cat3_id) FROM `cat3`),
            (SELECT COUNT(cat4_id) FROM `cat4`),
            (SELECT COUNT(cat5_id) FROM `cat5`),
            (SELECT COUNT(cat6_id) FROM `cat6`),
            (SELECT COUNT(cat7_id) FROM `cat7`)';

$stmt = $db->prepare($sql);
$stmt->execute();
$stmt->bind_result($var1, $var2, $var3, $var4, $var5, $var6, $var7, $var8);
$stmt->fetch();
$stmt->free_result();
$stmt->close();

while the seperate queries would look like this (x 8):

$sql = 'SELECT
            COUNT(cat1_id)
        FROM
            `cat1`';

$stmt = $db->prepare($sql);
$stmt->execute();
$stmt->bind_result($var1);
$stmt->fetch();
$stmt->free_result();
$stmt->close();

so, which would be faster or "better style" related to this kind of query (e.g. statistics, counter..)