diff --git a/admin/systemsortprocess.php b/admin/systemsortprocess.php
index 78cd639c..63ab604a 100644
--- a/admin/systemsortprocess.php
+++ b/admin/systemsortprocess.php
@@ -148,7 +148,7 @@ while (!is_process_killed($process_id)) //check if process killed every $sleepin
 		AND ((apn.appointment_id IS NOT NULL) or qs.call_max = 0 or ((SELECT count(*) FROM `call` WHERE case_id = c.case_id) < qs.call_max))
 	AND (SELECT count(*) FROM `questionnaire_sample_quota` WHERE questionnaire_id = c.questionnaire_id AND sample_import_id = s.import_id AND quota_reached = 1) = 0
 		GROUP BY c.case_id
-		ORDER BY apn.end ASC, a.start ASC, qsep.priority DESC";
+		ORDER BY IF(ISNULL(apn.end),1,0),apn.end ASC, a.start ASC, qsep.priority DESC";
 	
 	$rs = $db->GetAll($sql);
 
diff --git a/functions/functions.operator.php b/functions/functions.operator.php
index 7f981672..207e3b71 100644
--- a/functions/functions.operator.php
+++ b/functions/functions.operator.php
@@ -445,7 +445,7 @@ function get_case_id($operator_id, $create = false)
 					AND ((apn.appointment_id IS NOT NULL) or qs.call_max = 0 or ((SELECT count(*) FROM `call` WHERE case_id = c.case_id) < qs.call_max))
 					AND (apn.require_operator_id IS NULL OR apn.require_operator_id = '$operator_id')
 					AND (SELECT count(*) FROM `questionnaire_sample_quota` WHERE questionnaire_id = c.questionnaire_id AND sample_import_id = s.import_id AND quota_reached = 1) = 0
-					ORDER BY apn.end ASC, a.start ASC, qsep.priority DESC
+					ORDER BY IF(ISNULL(apn.end),1,0),apn.end ASC, a.start ASC, qsep.priority DESC
 					LIMIT 1";
 		
 					//apn.appointment_id contains the id of an appointment if we are calling on an appointment