fix: aggregate user model stats by requested model

backend/internal/repository/usage_log_repo.go

@@ -2786,42 +2786,7 @@ func (r *usageLogRepository) GetUserUsageTrendByUserID(ctx context.Context, user
 
 // GetUserModelStats 获取指定用户的模型统计
 func (r *usageLogRepository) GetUserModelStats(ctx context.Context, userID int64, startTime, endTime time.Time) (results []ModelStat, err error) {
-	query := `
-		SELECT
-			model,
-			COUNT(*) as requests,
-			COALESCE(SUM(input_tokens), 0) as input_tokens,
-			COALESCE(SUM(output_tokens), 0) as output_tokens,
-			COALESCE(SUM(cache_creation_tokens), 0) as cache_creation_tokens,
-			COALESCE(SUM(cache_read_tokens), 0) as cache_read_tokens,
-			COALESCE(SUM(input_tokens + output_tokens + cache_creation_tokens + cache_read_tokens), 0) as total_tokens,
-			COALESCE(SUM(total_cost), 0) as cost,
-			COALESCE(SUM(actual_cost), 0) as actual_cost,
-			COALESCE(SUM(COALESCE(account_stats_cost, total_cost) * COALESCE(account_rate_multiplier, 1)), 0) as account_cost
-		FROM usage_logs
-		WHERE user_id = $1 AND created_at >= $2 AND created_at < $3
-		GROUP BY model
-		ORDER BY total_tokens DESC
-	`
-
-	rows, err := r.sql.QueryContext(ctx, query, userID, startTime, endTime)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		// 保持主错误优先；仅在无错误时回传 Close 失败。
-		// 同时清空返回值，避免误用不完整结果。
-		if closeErr := rows.Close(); closeErr != nil && err == nil {
-			err = closeErr
-			results = nil
-		}
-	}()
-
-	results, err = scanModelStatsRows(rows)
-	if err != nil {
-		return nil, err
-	}
-	return results, nil
+	return r.getModelStatsWithFiltersBySource(ctx, startTime, endTime, userID, 0, 0, 0, "", nil, nil, nil, usagestats.ModelSourceRequested, "")
 }
 
 // UsageLogFilters represents filters for usage log queries

backend/internal/repository/usage_log_repo_request_type_test.go

@@ -434,6 +434,28 @@ func TestUsageLogRepositoryGetModelStatsWithFiltersRequestTypePriority(t *testin
 	require.NoError(t, mock.ExpectationsWereMet())
 }
 
+func TestUsageLogRepositoryGetUserModelStatsUsesRequestedModel(t *testing.T) {
+	db, mock := newSQLMock(t)
+	repo := &usageLogRepository{sql: db}
+
+	start := time.Date(2025, 1, 1, 0, 0, 0, 0, time.UTC)
+	end := start.Add(24 * time.Hour)
+
+	mock.ExpectQuery("(?s)SELECT\\s+COALESCE\\(NULLIF\\(TRIM\\(requested_model\\), ''\\), model\\) as model,.*WHERE created_at >= \\$1 AND created_at < \\$2\\s+AND user_id = \\$3.*GROUP BY COALESCE\\(NULLIF\\(TRIM\\(requested_model\\), ''\\), model\\) ORDER BY total_tokens DESC").
+		WithArgs(start, end, int64(7)).
+		WillReturnRows(sqlmock.NewRows([]string{
+			"model", "requests", "input_tokens", "output_tokens",
+			"cache_creation_tokens", "cache_read_tokens", "total_tokens",
+			"cost", "actual_cost", "account_cost",
+		}).AddRow("gpt-5.5", int64(2), int64(10), int64(20), int64(0), int64(0), int64(30), 0.1, 0.08, 0.07))
+
+	stats, err := repo.GetUserModelStats(context.Background(), 7, start, end)
+	require.NoError(t, err)
+	require.Len(t, stats, 1)
+	require.Equal(t, "gpt-5.5", stats[0].Model)
+	require.NoError(t, mock.ExpectationsWereMet())
+}
+
 func TestUsageLogRepositoryGetStatsWithFiltersRequestedModelSource(t *testing.T) {
 	db, mock := newSQLMock(t)
 	repo := &usageLogRepository{sql: db}