[Awards] Fix error when no bands are selected for POTA, SOTA and WWFF

application/models/Pota.php

@@ -15,6 +15,8 @@ class Pota extends CI_Model {
 
 		$bandslots = $this->bands->get_worked_bands('pota');
 
+		if(!$bandslots) return null;
+
 		$this->db->where_in("station_id", $logbooks_locations_array);
 		$this->db->where_in("col_band", $bandslots);
 		$this->db->order_by("COL_POTA_REF", "ASC");

application/models/Sota.php

@@ -15,6 +15,8 @@ class Sota extends CI_Model {
 
 		$bandslots = $this->bands->get_worked_bands('sota');
 
+		if(!$bandslots) return null;
+
 		$this->db->where_in("station_id", $logbooks_locations_array);
 		$this->db->where_in("col_band", $bandslots);
 		$this->db->order_by("COL_SOTA_REF", "ASC");

application/models/Wwff.php

@@ -15,6 +15,8 @@ class Wwff extends CI_Model {
 
 		$bandslots = $this->bands->get_worked_bands('wwff');
 
+		if(!$bandslots) return null;
+
 		$this->db->where_in("station_id", $logbooks_locations_array);
 		$this->db->where_in("col_band", $bandslots);
 		$this->db->order_by("COL_WWFF_REF", "ASC");