<br />
<b>Fatal error</b>:  Uncaught Exception: Error: MySQL server has gone away&lt;br /&gt;Error No: 2006&lt;br /&gt;
SELECT id.product_id FROM(SELECT 
    product_id, count(i.product_id) as t, c.filter_group as b
FROM
    (SELECT 
        f.filter_id, f.product_id, p.filter_group_id
    FROM
        oc_product_filter f
    left join oc_filter p ON p.filter_id = f.filter_id
    where
        p.filter_id IN (18)
    GROUP BY product_id , filter_group_id) as i,
    (select 
        count(distinct filter_group_id) as filter_group
    from
        oc_filter_description f_b
    WHERE f_b.filter_id in (18)) as c
GROUP BY product_id
HAVING t = b) as id in /home/lunast/domains/lunastar.nl/public_html/system/library/db/mysqli.php:40
Stack trace:
#0 /home/lunast/domains/lunastar.nl/public_html/system/library/db.php(16): DB\MySQLi-&gt;query('\nSELECT id.prod...', Array)
#1 /home/lunast/domains/lunastar.nl/public_html/system/storage/modification/catalog/model/catalog/product.php(620): DB-&gt;query('\nSELECT id.prod...')
#2 /home/lunast/domains/lunastar.nl/public_h in <b>/home/lunast/domains/lunastar.nl/public_html/system/library/db/mysqli.php</b> on line <b>40</b><br />