diff --git a/go/vehicle-gateway/internal/history/query.go b/go/vehicle-gateway/internal/history/query.go
index c2f08cd5..da35b069 100644
--- a/go/vehicle-gateway/internal/history/query.go
+++ b/go/vehicle-gateway/internal/history/query.go
@@ -169,7 +169,7 @@ func (r *RawFrameRepository) Query(ctx context.Context, query RawFrameQuery) ([]
 	}
 	defer rows.Close()
 
-	var out []RawFrameRow
+	out := make([]RawFrameRow, 0)
 	for rows.Next() {
 		var row RawFrameRow
 		var ts scanDateTime
@@ -222,7 +222,7 @@ func (r *LocationRepository) Query(ctx context.Context, query LocationQuery) ([]
 	}
 	defer rows.Close()
 
-	var out []LocationRow
+	out := make([]LocationRow, 0)
 	for rows.Next() {
 		var row LocationRow
 		var ts scanDateTime
@@ -282,7 +282,7 @@ func (r *MileagePointRepository) Query(ctx context.Context, query MileagePointQu
 	}
 	defer rows.Close()
 
-	var out []MileagePointRow
+	out := make([]MileagePointRow, 0)
 	for rows.Next() {
 		var row MileagePointRow
 		var ts scanDateTime
diff --git a/go/vehicle-gateway/internal/history/query_test.go b/go/vehicle-gateway/internal/history/query_test.go
index db411905..1c206078 100644
--- a/go/vehicle-gateway/internal/history/query_test.go
+++ b/go/vehicle-gateway/internal/history/query_test.go
@@ -135,6 +135,39 @@ func TestRawFrameHandlerFiltersByVehicleKey(t *testing.T) {
 	}
 }
 
+func TestRawFrameHandlerReturnsEmptyItemsArrayWhenNoRows(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("sqlmock.New() error = %v", err)
+	}
+	defer db.Close()
+	mock.ExpectQuery("SELECT COUNT\\(\\*\\) FROM lingniu_vehicle_ts.raw_frames").
+		WillReturnRows(sqlmock.NewRows([]string{"total"}).AddRow(0))
+	mock.ExpectQuery("SELECT ts, frame_id, event_id, message_id, event_time, received_at, raw_size_bytes, raw_hex, raw_text, parsed_json, fields_json, parse_status, parse_error, source_endpoint, protocol, vehicle_key, vin, phone, device_id FROM lingniu_vehicle_ts.raw_frames").
+		WillReturnRows(sqlmock.NewRows([]string{
+			"ts", "frame_id", "event_id", "message_id", "event_time", "received_at", "raw_size_bytes",
+			"raw_hex", "raw_text", "parsed_json", "fields_json", "parse_status", "parse_error", "source_endpoint",
+			"protocol", "vehicle_key", "vin", "phone", "device_id",
+		}))
+
+	handler := NewRawFrameHandler(NewRawFrameRepository(db, "lingniu_vehicle_ts"))
+	request := httptest.NewRequest(http.MethodGet, "/api/history/raw-frames?protocol=NOT_EXISTS&limit=1", nil)
+	response := httptest.NewRecorder()
+
+	handler.ServeHTTP(response, request)
+
+	if response.Code != http.StatusOK {
+		t.Fatalf("status = %d body=%s", response.Code, response.Body.String())
+	}
+	body := response.Body.String()
+	if !strings.Contains(body, `"items":[]`) || strings.Contains(body, `"items":null`) {
+		t.Fatalf("expected empty items array, got: %s", body)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatalf("sql expectations: %v", err)
+	}
+}
+
 func TestLocationHandlerReturnsLocationsByVehicleKey(t *testing.T) {
 	db, mock, err := sqlmock.New()
 	if err != nil {
diff --git a/go/vehicle-gateway/internal/stats/query.go b/go/vehicle-gateway/internal/stats/query.go
index e735ec47..052ea3da 100644
--- a/go/vehicle-gateway/internal/stats/query.go
+++ b/go/vehicle-gateway/internal/stats/query.go
@@ -63,7 +63,7 @@ func (r *MetricRepository) Query(ctx context.Context, query MetricQuery) ([]Metr
 	}
 	defer rows.Close()
 
-	var out []MetricRow
+	out := make([]MetricRow, 0)
 	for rows.Next() {
 		var row MetricRow
 		var statDate scanDate
diff --git a/go/vehicle-gateway/internal/stats/query_test.go b/go/vehicle-gateway/internal/stats/query_test.go
index da354eb0..ca7e4ab7 100644
--- a/go/vehicle-gateway/internal/stats/query_test.go
+++ b/go/vehicle-gateway/internal/stats/query_test.go
@@ -137,6 +137,41 @@ func TestMetricHandlerFiltersByVehicleKey(t *testing.T) {
 	}
 }
 
+func TestMetricHandlerReturnsEmptyItemsArrayWhenNoRows(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("sqlmock.New() error = %v", err)
+	}
+	defer db.Close()
+	mock.ExpectQuery("SELECT COUNT\\(\\*\\) FROM vehicle_daily_metric").
+		WithArgs("YUTONG_MQTT").
+		WillReturnRows(sqlmock.NewRows([]string{"total"}).AddRow(0))
+	mock.ExpectQuery("SELECT vehicle_key, vin, stat_date, protocol, metric_key, metric_value, metric_unit, first_total_mileage_km, latest_total_mileage_km, sample_count, calculation_method, created_at, updated_at FROM vehicle_daily_metric").
+		WithArgs("YUTONG_MQTT", 50, 0).
+		WillReturnRows(sqlmock.NewRows([]string{
+			"vehicle_key", "vin", "stat_date", "protocol", "metric_key", "metric_value", "metric_unit",
+			"first_total_mileage_km", "latest_total_mileage_km", "sample_count", "calculation_method",
+			"created_at", "updated_at",
+		}))
+
+	handler := NewMetricHandler(NewMetricRepository(db))
+	request := httptest.NewRequest(http.MethodGet, "/api/stats/daily-metrics?protocol=YUTONG_MQTT", nil)
+	response := httptest.NewRecorder()
+
+	handler.ServeHTTP(response, request)
+
+	if response.Code != http.StatusOK {
+		t.Fatalf("status = %d body=%s", response.Code, response.Body.String())
+	}
+	body := response.Body.String()
+	if !strings.Contains(body, `"items":[]`) || strings.Contains(body, `"items":null`) {
+		t.Fatalf("expected empty items array, got: %s", body)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatalf("sql expectations: %v", err)
+	}
+}
+
 func TestMetricHandlerRejectsInvalidPagination(t *testing.T) {
 	handler := NewMetricHandler(NewMetricRepository(&sql.DB{}))
 	request := httptest.NewRequest(http.MethodGet, "/api/stats/daily-metrics?limit=2001", nil)