C# EF+LINQ 查询主表明细表数据查询条件写法

            //主从表的统一查询内容
            if (!input.content.IsEmpty())
            {
                //查询明细(子查询）
                var q_Sub = q_APs.Where(w => false
                     || w.InvoiceNo == input.content
                     || w.InvoiceName == input.content
                     || w.OrderNo == input.content
                     || (w.Remark ?? "").Contains(input.content));

                //主表
                q_AP = q_AP.Where(w => (false
                    || w.APNO == input.content
                    || w.SupplierCode == input.content
                    || (w.SupplierName ?? "").Contains(input.content)) || q_Sub.Any(x => x.APNO == w.APNO));
            }


            return q_AP.ToList();

        public List<res_tb_SS> Query(req_SS input)
        {
            var q_SS = _Database.GetQueryable<tb_SS>(); //主表
            var q_SSs = _Database.GetQueryable<tb_SSs>(); //从表
            
            //明细表单独的过滤器
            var q_Filter = _Database.GetQueryable<tb_SSs>(); 

            if (!input.DZNO.IsEmpty())
                q_SS = q_SS.Where(w => w.DZNO == input.DZNO);

            if (input.DocDateFrom > Globals.MinSqlDate)//1900-01-01
            {
                q_SS = q_SS.Where(w => w.DocDate >= input.DocDateFrom);
            }

            if (input.DocDateTo > Globals.MinSqlDate)
            {
                q_SS = q_SS.Where(w => w.DocDate <= input.DocDateTo);
            }

            if (!input.DocType.IsEmpty())
                q_SS = q_SS.Where(w => w.DocType == input.DocType);

            if (!input.PaymentType.IsEmpty())
                q_SS = q_SS.Where(w => w.PaymentType == input.PaymentType);

            if (!input.SupplierCode.IsEmpty())
                q_SS = q_SS.Where(w => w.SupplierCode == input.SupplierCode);

            // 模糊匹配 content
            if (!input.content.IsEmpty())
            {
                // 先筛选从表
                q_Filter = q_SSs.Where(w =>
                    w.DocNo == input.content ||
                    w.ProductCode == input.content ||
                    w.CustomerOrderNo == input.content ||
                    (w.DocRemark != null && w.DocRemark.Contains(input.content)) ||
                    (w.ProductName != null && w.ProductName.Contains(input.content)) ||
                    (w.Model != null && w.Model.Contains(input.content)) ||
                    (w.Remark != null && w.Remark.Contains(input.content)));

                // 主表条件 + 关联从表条件
                q_SS = q_SS.Where(w =>
                    w.DZNO == input.content ||
                    w.SupplierCode == input.content ||
                    w.SupplierContact == input.content ||
                    w.SupplierContactTel == input.content ||
                    (w.SupplierName != null && w.SupplierName.Contains(input.content)) ||
                    (w.Remark != null && w.Remark.Contains(input.content)) ||
                    q_Filter.Any(x => x.DZNO == w.DZNO)); // 这里使用已筛选的 q_SSs                    
            }

            var resList = from a in q_SS
                          //关键： 如果 input.content 为空，则不过滤从表
                          join b in q_SSs.Where(w => input.content.IsEmpty() || q_Filter.Any(x => x.isid == w.isid))
                          on a.DZNO equals b.DZNO into tmp
                          from b in tmp.DefaultIfEmpty()
                          select new res_tb_SS
                          {
                              //主表
                              isid = a.isid,
                              DZNO = a.DZNO,
                              DocDate = a.DocDate,
                              SupplierCode = a.SupplierCode,
                              SupplierName = a.SupplierName,
                              SupplierContact = a.SupplierContact,
                              SupplierContactTel = a.SupplierContactTel,
                              PaymentType = a.PaymentType,
                              TotalAmount = a.TotalAmount,
                              TotalAmountExclTax = a.TotalAmountExclTax,
                              TotalTaxAmount = a.TotalTaxAmount,
                              TotalSettleAmount = a.TotalSettleAmount,
                              TotalSettleAmountBal = a.TotalSettleAmountBal,
                              Remark = a.Remark,
                              Year = a.Year,
                              Month = a.Month,
                              FlagPeriod = a.FlagPeriod,
                              PeriodId = a.PeriodId,
                              FlagApp = a.FlagApp,
                              AppUser = a.AppUser,
                              AppDate = a.AppDate,
                              CreationDate = a.CreationDate,
                              CreatedBy = a.CreatedBy,
                              LastUpdateDate = a.LastUpdateDate,
                              LastUpdatedBy = a.LastUpdatedBy,

                              //明细表
                              isid_detail = b == null ? null : b.isid,
                              Queue = b == null ? null : b.Queue,
                              OrderId = b == null ? null : b.OrderId,

                              DocNo = b == null ? null : b.DocNo,

                              DocDetail_isid = b == null ? null : b.DocDetail_isid,
                              DocOrderId = b == null ? null : b.DocOrderId,
                              DocType = b == null ? null : b.DocType,
                              DocDate_detail = b == null ? null : b.DocDate,
                              DocRemark = b == null ? null : b.DocRemark,
                              PONO = b == null ? null : b.PONO,
                              ARAP = b == null ? null : b.ARAP,
                              LocationID = b == null ? null : b.LocationID,
                              ProductCode = b == null ? null : b.ProductCode,
                              ProductName = b == null ? null : b.ProductName,
                              ProductType = b == null ? null : b.ProductType,
                              Model = b == null ? null : b.Model,
                              CustomerOrderNo = b == null ? null : b.CustomerOrderNo,
                              Unit = b == null ? null : b.Unit,
                              OrderQty = b == null ? null : b.OrderQty,
                              Quantity = b == null ? null : b.Quantity,
                              Price = b == null ? null : b.Price,
                              Amount = b == null ? null : b.Amount,
                              PriceExclTax = b == null ? null : b.PriceExclTax,
                              AmountExclTax = b == null ? null : b.AmountExclTax,
                              TaxRate = b == null ? null : b.TaxRate,
                              TaxAmount = b == null ? null : b.TaxAmount,
                              Currency = b == null ? null : b.Currency,
                              CurrencyRate = b == null ? null : b.CurrencyRate,
                              SettleAmount = b == null ? null : b.SettleAmount,
                              SettleAmountBal = b == null ? null : b.SettleAmountBal,
                          };

            var resultList = new List<res_tb_SS>();

            if (input.top > 0)
                resultList = resList.Distinct().Take(input.top).OrderByDescending(o => o.CreationDate).ToList();
            else
                resultList = resList.Distinct().OrderByDescending(o => o.CreationDate).ToList();

            //返回查询结果
            return resultList.ToList();
        }