Linq:非等值左连接,该如何处理

    public class CarcassLeans
    {
        public long OBS { get; set; }
        public double CarcassWeight { get; set; }
        public double PredictedLiveWeight { get; set; }
        public double CarcassLean { get; set; }
        public double CarcassYield { get; set; }
        public double MatrixValue { get; set; }
        public double TotalFeedCost { get; set; }
        public double Avg_CarcassWeight { get; set; }

        public CarcassLeans()
        {

        }
    }
    public class DM_Matrix
    {
        public int ID { get; set; }
        public double MatrixValue { get; set; }
        public double MinColumn { get; set; }
        public double MaxColumn { get; set; }
        public double MinRow { get; set; }
        public double MaxRow { get; set; }
        public string Packer { get; set; }


        public DM_Matrix()
        {

        }
    }