fix(graphql): fix sort by relation (#967)

app/Concerns/Actions/GraphQL/SortsModels.php

@@ -74,6 +74,20 @@ trait SortsModels
             }
 
             if ($sortType === SortType::RELATION) {
+                if ($relation === null) {
+                    throw new InvalidArgumentException("The 'relation' argument is required for the {$column} column with aggregate sort type.");
+                }
+
+                $builder->withAggregate([
+                    "$relation as {$relation}_$column" => function ($query) use ($column, $direction) {
+                        $query->orderBy($column, $direction);
+                    },
+                ], $column);
+
+                $builder->orderBy("{$relation}_$column", $direction);
+            }
+
+            if ($sortType === SortType::COUNT_RELATION) {
                 if ($relation === null) {
                     throw new InvalidArgumentException("The 'relation' argument is required for the {$column} column with relation sort type.");
                 }

app/Enums/GraphQL/SortType.php

@@ -10,4 +10,5 @@ enum SortType: int
     case ROOT = 1;
     case AGGREGATE = 2;
     case RELATION = 3;
+    case COUNT_RELATION = 4;
 }

app/GraphQL/Schema/Fields/Base/CountField.php

@@ -34,7 +34,7 @@ class CountField extends Field implements DisplayableField, SortableField
 
     public function sortType(): SortType
     {
-        return SortType::RELATION;
+        return SortType::COUNT_RELATION;
     }
 
     /**