diff --git a/application/Espo/ORM/DB/Query/Base.php b/application/Espo/ORM/DB/Query/Base.php
index 40a70abd24..363b2838b2 100644
--- a/application/Espo/ORM/DB/Query/Base.php
+++ b/application/Espo/ORM/DB/Query/Base.php
@@ -292,7 +292,7 @@ abstract class Base
                     if (!array_key_exists($field[0], $entity->fields)) {
                         $part = $this->convertComplexExpression($entity, $field[0], $distinct);
                     } else {
-                        $fieldDefs = $entity->fields[$field];
+                        $fieldDefs = $entity->fields[$field[0]];
                         if (!empty($fieldDefs['select'])) {
                             $part = $fieldDefs['select'];
                         } else {