bug修改

@@ -406,14 +406,16 @@ class User extends Backend
                     $my_study_ids = Db::name('third_study')->where('third_id',$third_id)->column('study_id');
                     if($my_study_ids){
                         $delete_study_ids = array_diff($my_study_ids,$study_ids);
-                        Db::name('third_study')
-                            ->where('third_id',$third_id)
-                            ->where('study_id','in',$delete_study_ids)
-                            ->delete();
-                        Db::name('study_class')
-                            ->where('third_id',$third_id)
-                            ->where('study_id','in',$delete_study_ids)
-                            ->delete();
+                        if($delete_study_ids){
+                            Db::name('third_study')
+                                ->where('third_id',$third_id)
+                                ->where('study_id','in',$delete_study_ids)
+                                ->delete();
+                            Db::name('study_class')
+                                ->where('third_id',$third_id)
+                                ->where('study_id','in',$delete_study_ids)
+                                ->delete();
+                        }
                     }
 
                     Db::commit();