取最后一个 VchNo 和按月分组并在实体框架中求和总金额
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【中文标题】取最后一个 VchNo 和按月分组并在实体框架中求和总金额【英文标题】：Take Last VchNo and Group by Month and Sum Total Amount in Entity Framework 【发布时间】：2021-07-20 19:27:59 【问题描述】：public partial class FeesVoucher
public long Auto_id get; set;
public string VoucherNo get; set;
public string StudentID get; set;
public string SessionID get; set;
public string ClassID get; set;
public string SectionID get; set;
public Nullable<System.DateTime> IssueDate get; set;
public Nullable<System.DateTime> DueDate get; set;
public Nullable<System.DateTime> FeesDate get; set;
public string FeeMonth get; set;
public string FeeYear get; set;
public Nullable<decimal> RegistrationFee get; set;
public Nullable<decimal> AdmissionFee get; set;
public Nullable<decimal> SecurityDeposit get; set;
public Nullable<decimal> TutionFee get; set;
public Nullable<decimal> Fine_Late_Fee get; set;
public Nullable<decimal> TransportCharges get; set;
public Nullable<decimal> Lab_ExaminationFee get; set;
public Nullable<decimal> AnnualCharges get; set;
public Nullable<decimal> BoardPECFee get; set;
public Nullable<decimal> OtherCharges get; set;
public Nullable<decimal> TotalAmount get; set;
public string FeesStatus get; set;
public string PaidType get; set;
public string CampusID get; set;
public string FeesID get; set;
public string VoucherMessages get; set;
public string CreatedBy get; set;
public Nullable<System.DateTime> CreatedDate get; set;
public string LastUpdateBy get; set;
public Nullable<System.DateTime> LastUpdated get; set;
public string EditMsg get; set;
public string IsEdit get; set;
public string RevAcc get; set;
public string RecAcc get; set;
using (Entities db = new Entities())
var dt = (from stu in db.StudentsInfoes
join CampusS in db.CampusSetups on stu.CampusID equals CampusS.CampusID
join stuclass in db.StudentClassInfoes on stu.StudentID equals stuclass.StudentID
join sectionID in db.ClassesSections on stuclass.ClassID equals sectionID.ClassID
join classs in db.ClassSetups on stuclass.ClassID equals classs.ClassID
join SessS in db.SessionsSetups on stuclass.SessionID equals SessS.SessionID
join FeeV in db.FeesVouchers on stu.StudentID equals FeeV.StudentID
select new
StudentID = stu.StudentID,
FullName = stu.FullName,
FatherName = stu.FatherName,
StStatus = stu.Status,
ClassStatus = stuclass.Status,
CampusID = CampusS.CampusID,
RollNo = stuclass.RollNo,
ClassID = stuclass.ClassID,
ClassDesc = classs.ClassDesc,
SectionID = sectionID.SectionID,
SectionDesc = sectionID.SectionDesc,
VoucherNo = FeeV.VoucherNo,
SessionID = SessS.SessionID,
Months = FeeV.FeeMonth,
RegistrationFee = FeeV.RegistrationFee,
AdmissionFee = FeeV.AdmissionFee,
AnnualCharges = FeeV.AnnualCharges,
SecurityDeposit = FeeV.SecurityDeposit,
Fine_Late_Fee = FeeV.Fine_Late_Fee,
BoardPECFee = FeeV.BoardPECFee,
Lab_ExaminationFee =
FeeV.Lab_ExaminationFee,
OtherCharges = FeeV.OtherCharges,
TutionFee = FeeV.TutionFee,
IssueDate = FeeV.IssueDate,
DueDate = FeeV.DueDate,
TotalAmount = FeeV.TotalAmount,
FeeStatus = FeeV.FeesStatus,
FeeYear = FeeV.FeeYear,
FeesID = FeeV.FeesID,
).Where(x => x.FeeStatus.Equals("unpaid")).Select(x => new x.VoucherNo,x.FullName,x.IssueDate,x.DueDate,x.Months,x.TotalAmount ).Distinct().ToList();
这个查询在没有分组和求和的情况下完美地工作，如图所示 ===> Without Group and Sum Picture 在多个表加入此查询后生成这样的结果
| VchNo | Student Name | Month | Total Amount |
|---|---|---|---|
| 0001 | aa | Jan | 2000 |
| 0002 | aa | Feb | 2000 |
| 0003 | aa | Mar | 2000 |
| 0004 | bb | Jan | 2000 |
| 0005 | bb | Feb | 2000 |
| 0006 | bb | Mar | 2000 |
但我想修改我的查询以实现分组和求和，如图所示 ===>With Group and Sum Picture 但我想取最后一个 VchNo 并按月分组并像这样总结总金额
| VchNo | Student Name | Month | Total Amount |
|---|---|---|---|
| 0003 | aa | Jan,Feb,Mar | 6000 |
| 0006 | bb | Jan,Feb,Mar | 6000 |
实体框架 6.0 的查询是什么 所有答案将不胜感激
【问题讨论】：
【参考方案1】：见下文：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
namespace ConsoleApplication
public class Program
public static void Main(string[] args)
DataTable dt = new DataTable();
dt.Columns.Add("VchNo", typeof(string));
dt.Columns.Add("Student Name", typeof(string));
dt.Columns.Add("Month", typeof(string));
dt.Columns.Add("Total Amount", typeof(int));
dt.Rows.Add(new object[] "0001", "aa", "Jan", 2000 );
dt.Rows.Add(new object[] "0002", "aa", "Feb", 2000 );
dt.Rows.Add(new object[] "0003", "aa", "Mar", 2000 );
dt.Rows.Add(new object[] "0004", "bb", "Jan", 2000 );
dt.Rows.Add(new object[] "0005", "bb", "Feb", 2000 );
dt.Rows.Add(new object[] "0006", "bb", "Mar", 2000 );
DataTable dt2 = dt.Clone();
var groups = dt.AsEnumerable().GroupBy(x => x.Field<string>("Student Name")).ToList();
foreach (var group in groups)
dt2.Rows.Add(new object[]
group.Select(x => x.Field<string>("VchNo")).LastOrDefault(),
group.Key,
string.Join(",", group.Select(XmlReadMode => XmlReadMode.Field<string>("Month"))),
group.Sum(x => x.Field<int>("Total Amount"))
);
使用实体：
class Program
static void Main(string[] args)
using (Entities db = new Entities())
var dt = (from stu in db.StudentsInfoes
join CampusS in db.CampusSetups on stu.CampusID equals CampusS.CampusID
join stuclass in db.StudentClassInfoes on stu.StudentID equals stuclass.StudentID
join sectionID in db.ClassesSections on stuclass.ClassID equals sectionID.ClassID
join classs in db.ClassSetups on stuclass.ClassID equals classs.ClassID
join SessS in db.SessionsSetups on stuclass.SessionID equals SessS.SessionID
join FeeV in db.FeesVouchers on stu.StudentID equals FeeV.StudentID
select new
StudentID = stu.StudentID,
FullName = stu.FullName,
FatherName = stu.FatherName,
StStatus = stu.Status,
ClassStatus = stuclass.Status,
CampusID = CampusS.CampusID,
RollNo = stuclass.RollNo,
ClassID = stuclass.ClassID,
ClassDesc = classs.ClassDesc,
SectionID = sectionID.SectionID,
SectionDesc = sectionID.SectionDesc,
VoucherNo = FeeV.VoucherNo,
SessionID = SessS.SessionID,
Months = FeeV.FeeMonth,
RegistrationFee = FeeV.RegistrationFee,
AdmissionFee = FeeV.AdmissionFee,
AnnualCharges = FeeV.AnnualCharges,
SecurityDeposit = FeeV.SecurityDeposit,
Fine_Late_Fee = FeeV.Fine_Late_Fee,
BoardPECFee = FeeV.BoardPECFee,
Lab_ExaminationFee =
FeeV.Lab_ExaminationFee,
OtherCharges = FeeV.OtherCharges,
TutionFee = FeeV.TutionFee,
IssueDate = FeeV.IssueDate,
DueDate = FeeV.DueDate,
TotalAmount = FeeV.TotalAmount,
FeeStatus = FeeV.FeesStatus,
FeeYear = FeeV.FeeYear,
FeesID = FeeV.FeesID,
).Where(x => x.FeeStatus.Equals("unpaid")).Select(x => new x.VoucherNo, x.FullName, x.IssueDate, x.DueDate, x.Months, x.TotalAmount ).Distinct().ToList();
var results = dt.GroupBy(x => x.FullName).Select(x => new
VchNo = x.Last().VoucherNo,
Name = x.Key,
Months = string.Join(",", x.Select(y => y.Months)),
Amount = x.Sum(y => y.TotalAmount)
).ToList();
public class Entities : IDisposable
public List<CampusSetups> CampusSetups get; set;
public List<ClassSetups> ClassSetups get; set;
public List<ClassesSections> ClassesSections get; set;
public List<FeesVoucher> FeesVouchers get; set;
public string SectionsSetups get; set;
public List<StudentsInfoes> StudentsInfoes get; set;
public List<StudentClassInfoes> StudentClassInfoes get; set;
public List<SessionsSetups> SessionsSetups get; set;
public void Dispose()
public class ClassSetups
public string ClassID get; set;
public string ClassDesc get; set;
public class ClassesSections
public string ClassID get; set;
public string SectionDesc get; set;
public string SectionID get; set;
public class SessionsSetups
public string SessionID get; set;
public class StudentClassInfoes
public string StudentID get; set;
public string ClassID get; set;
public string SessionID get; set;
public string RollNo get; set;
public string Status get; set;
public class CampusSetups
public string CampusID get; set;
public class StudentsInfoes
public string CampusID get; set;
public string StudentID get; set;
public string FatherName get; set;
public string FullName get; set;
public string Status get; set;
public partial class FeesVoucher
public long Auto_id get; set;
public string VoucherNo get; set;
public string StudentID get; set;
public string SessionID get; set;
public string ClassID get; set;
public string SectionID get; set;
public Nullable<System.DateTime> IssueDate get; set;
public Nullable<System.DateTime> DueDate get; set;
public Nullable<System.DateTime> FeesDate get; set;
public string FeeMonth get; set;
public string FeeYear get; set;
public Nullable<decimal> RegistrationFee get; set;
public Nullable<decimal> AdmissionFee get; set;
public Nullable<decimal> SecurityDeposit get; set;
public Nullable<decimal> TutionFee get; set;
public Nullable<decimal> Fine_Late_Fee get; set;
public Nullable<decimal> TransportCharges get; set;
public Nullable<decimal> Lab_ExaminationFee get; set;
public Nullable<decimal> AnnualCharges get; set;
public Nullable<decimal> BoardPECFee get; set;
public Nullable<decimal> OtherCharges get; set;
public Nullable<decimal> TotalAmount get; set;
public string FeesStatus get; set;
public string PaidType get; set;
public string CampusID get; set;
public string FeesID get; set;
public string VoucherMessages get; set;
public string CreatedBy get; set;
public Nullable<System.DateTime> CreatedDate get; set;
public string LastUpdateBy get; set;
public Nullable<System.DateTime> LastUpdated get; set;
public string EditMsg get; set;
public string IsEdit get; set;
public string RevAcc get; set;
public string RecAcc get; set;
【讨论】：
非常感谢自定义数据表。我想要关于 LINQ 或实体框架上下文的任何建议！ Linq 是一个查询，并不意味着将数据添加到数据表中。代码很容易转换为实体。 谢谢，兄弟。问题已更新。现在您可以为我提出更好的解决方案吗？ Distinct 真的有效吗？您需要以下内容才能工作：docs.microsoft.com/en-us/dotnet/api/… 添加实体解决方案【参考方案2】：也许是这样的
collection.GroupBy(x => x.StudentName).Select(g =>
new
g.Last().VchNo,
g.Last().StudentName,
Month = string.Join(',', g.Select(gg => g.Month)),
TotalAmount = g.Sum(gg => g.TotalAmount)
);
我猜到了属性名称，因为您没有包含它们。修改代码以替换您的实际实体名称
【讨论】：
g.Month 和 g.TotalAmount 显示错误“不包含 Month 和 TotalAmount 的定义 您没有指定您的客户端属性名称是什么（但它们肯定不能包含空格！）您只是说数据库表的样子（您的列名真的包含空格？？） .您必须将它们更改为您的实际属性名称。如果您没有在问题中提供完整的信息，您通常必须接受答案可能无法直接复制粘贴；仍然需要你的努力 非常感谢。我已经用代码和两张图片更新了我的问题。现在你可以建议我更好的查询。以上是关于取最后一个 VchNo 和按月分组并在实体框架中求和总金额的主要内容，如果未能解决你的问题，请参考以下文章