diff --git a/src/Plugin/GraphQL/Fields/SearchAPISearch.php b/src/Plugin/GraphQL/Fields/SearchAPISearch.php
index 23b8148..ace8a02 100644
--- a/src/Plugin/GraphQL/Fields/SearchAPISearch.php
+++ b/src/Plugin/GraphQL/Fields/SearchAPISearch.php
@@ -169,7 +169,7 @@ private function addConditionGroup($condition_group_arg) {
       // Loop through all conditions and add them to the Group.
       foreach ($group['conditions'] as $condition) {
 
-        $condition_group->addCondition($condition['name'], $condition['value'], $condition['operator']);
+        $condition_group->addCondition($condition['name'], $condition['value'] ?? NULL, $condition['operator'] ?? '=');
       }
 
       // Merge the single groups to the condition group.