//重写比较方法
        public class SkuEqualityComparer : IEqualityComparer<Sku>
        {
            public bool Equals(Sku x, Sku y)
            {
                return x.color== y.color&& x.itemno== y.itemno&& x.size== y.size;
            }

            public int GetHashCode(Sku obj)
            {
                if (obj == null)
                {
                    return 0;
                }
                else
                {
                    return obj.ToString().GetHashCode();
                }
            }
        }

public Tuple<bool, string> AddSku(List<Sku> model)
        {

           
            List<string> list = new List<string>();
           
            //假设从数据库查出来1,2,5
            var isExsit = _skuRepository.GetSkuList(where);//where条件此处省略
            //前端传来的model  2,3,4,5
           //那么我需要比对出来的是2,5
            if (isExsit.Count() > 0)
            {
                //只取出sku颜色，货号，尺码相同的交集(2,5)
                var sqlData = model.Intersect(isExsit, new SkuEqualityComparer()).ToList();
            //遍历当前list
                foreach (var item in sqlData)
                {
                    //查询当前数据信息(2)                  
                    var sku= _skuRepository.GetSkuList(where1).FirstOrDefault();//where1条件此处省略
                    //对比客户端的(2)和数据库的(2)有效期是否相同
                    if (item.price!= sku.price)
                    {
                        //如果有效期不同，则在记录表插入
                      list.Add($"insert into skuInfo (name) values ('sku的name')");
                      
                    }
                }
    
                list.Add($"delete from Sku where 1=1  {where}");
                return _skuRepository.AddSkuInfo(model, list);
            }
            else
            {                
                return _skuRepository.AddSkuInfo(model, list);
            }

        }