diff --git a/poll-billing.php b/poll-billing.php
index 4985af8450..1733db23c0 100755
--- a/poll-billing.php
+++ b/poll-billing.php
@@ -42,7 +42,7 @@ foreach ($query->get(['bill_id', 'bill_name']) as $bill) {
     $bill_id = $bill->bill_id;
 
     if ($config['distributed_poller'] && $config['distributed_billing']) {
-        $port_list = dbFetchRows('SELECT * FROM `bill_ports` as P, `ports` as I, `devices` as D WHERE P.bill_id=? AND I.port_id = P.port_id AND I.ifOperStatus="up" AND D.device_id = I.device_id AND D.status=1 AND D.poller_group IN ('.$config['distributed_poller_group'].')', [$bill_id]);
+        $port_list = dbFetchRows('SELECT * FROM `bill_ports` as P, `ports` as I, `devices` as D WHERE P.bill_id=? AND I.port_id = P.port_id AND I.ifOperStatus="up" AND D.device_id = I.device_id AND D.status=1 AND D.poller_group IN (' . $config['distributed_poller_group'] . ')', [$bill_id]);
     } else {
         $port_list = dbFetchRows('SELECT * FROM `bill_ports` as P, `ports` as I, `devices` as D WHERE P.bill_id=? AND I.port_id = P.port_id AND I.ifOperStatus="up" AND D.device_id = I.device_id AND D.status=1', [$bill_id]);
     }
@@ -144,7 +144,7 @@ foreach ($query->get(['bill_id', 'bill_name']) as $bill) {
     } else {
         // NOTE: casting to string for mysqli bug (fixed by mysqlnd)
         if ($config['distributed_poller'] && $config['distributed_billing']) {
-            $port_count = dbFetchCell('SELECT COUNT(*) FROM `bill_ports` as P, `ports` as I, `devices` as D WHERE P.bill_id=? AND I.port_id = P.port_id AND D.device_id = I.device_id AND D.poller_group IN ('.$config['distributed_poller_group'].')', [$bill_id]);
+            $port_count = dbFetchCell('SELECT COUNT(*) FROM `bill_ports` as P, `ports` as I, `devices` as D WHERE P.bill_id=? AND I.port_id = P.port_id AND D.device_id = I.device_id AND D.poller_group IN (' . $config['distributed_poller_group'] . ')', [$bill_id]);
         } else {
             $port_count = dbFetchCell('SELECT COUNT(*) FROM `bill_ports` as P, `ports` as I, `devices` as D WHERE P.bill_id=? AND I.port_id = P.port_id AND D.device_id = I.device_id', [$bill_id]);
         }