diff --git a/sql/item_func.cc b/sql/item_func.cc
index 0cd6ff6357e..be8ee84712a 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4023,7 +4023,8 @@ longlong Item_func_last_insert_id::val_int()
     thd->first_successful_insert_id_in_prev_stmt= value;
     return value;
   }
-  return thd->read_first_successful_insert_id_in_prev_stmt();
+  return
+    static_cast<longlong>(thd->read_first_successful_insert_id_in_prev_stmt());
 }
 
 
diff --git a/sql/item_func.h b/sql/item_func.h
index 9198b092539..6ac0b1b82bd 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -1130,6 +1130,7 @@ public:
   const char *func_name() const { return "last_insert_id"; }
   void fix_length_and_dec()
   {
+    unsigned_flag= TRUE;
     if (arg_count)
       max_length= args[0]->max_length;
   }