在SQL Server中加入逗号分隔值

我正在用LINQ写一个问题加入li。 如何获得包含3个表组合的结果表？ 我必须将表格合并在一行中。 有任何想法吗？

Peole --------------- Id | 1 Id |2 Name | David Name |Ameyy Surname| David1 Surname |Ameyy2 Appointment --------------- Id |19 PeopleId |1 Subject |description Participant --------------- Id |1 Id |2 AppointmentId |19 AppointmentId |19 PeopleId |1 PeopleId |2 Result ---------------------------------- Id | 1 Subject | Subject Participant| David David1, Ameyy Ameyy2 

Linq查询;

  IQueryable query = db.Randevu.Join(db.Kisi, appointment => appointment .TALEPEDENKISI, people=> people.ID, (appointment , people) => new AppointmentPoolModel { Id = appointment.ID, Subject = appointment.Subject, Note = appointment .NOTLAR, NameSurname = people.Name+ " " + people.Surname, RequestedId = people.ID, //Participan = string.Join(",", ) }); var result = query.OrderBy(appointment => randevu.AppointmentStartDate).ToList(); 

Answer 1

你可以试试这个。

 var qPeoples = Participants.Join(Peoples, pr => pr.PeopleId, pe => pe.Id, (pr, pe) => new { Part = pr, People = pe }); var result = Appointments.Select(app => new { app.Id, app.Subject, Participant = String.Join(",", qPeoples.Where(q => q.Part.AppointmentId == app.Id) .Select(s => new { FullName = String.Format( "{0} {1}" , s.People.Name, s.People.Surname ) } ) ) }).ToList(); 

Answer 2

你应该逐步调查。

这里有一个带有两个专用连接和一个groupBy的示例（在您的情况下缺少）：

 public class People { public int Id { get; set; } public string Name { get; set; } public string Surname { get; set; } } public class Appointment { public int Id { get; set; } public string Subject { get; set; } } public class Participation { public int Id { get; set; } public int PeopleId { get; set; } public int AppointmentId { get; set; } } static void Main(string[] args) { // Example-Data (Would have helped in this format ;)) List people = new List() { new People() { Id = 1, Surname = "David1", Name = "David"}, new People() { Id = 2, Surname = "Ameyy2", Name = "Ameyy"} }; List appointments = new List() { new Appointment() { Id = 1, Subject = "description" } }; List participations = new List() { new Participation() { Id = 1, PeopleId = 1, AppointmentId = 1 }, new Participation() { Id = 1, PeopleId = 2, AppointmentId = 1 } }; Console.WriteLine("***** JOIN appointment to participation *****"); // At the beginning we want to join the table 'Appointment' with the n-to-n-Table "Participation". var AppointmentsAndParticipations = appointments.Join ( participations, // Other table to connect a => a.Id, // Key in 1st table p => p.AppointmentId, // Key in 2nd table (a, p) => new { Appointment = a, PeopleId = p.PeopleId } // build new row ); foreach (var item in AppointmentsAndParticipations) { // The result should be out appointment and the peopleId. We got "Appointment.Count*Participations.Count" rows Console.WriteLine(item.Appointment.Id.ToString().PadLeft(5) + ", " + item.Appointment.Subject.PadLeft(15) + ", " + item.PeopleId); } Console.WriteLine("***** JOIN people *****"); // We need to join the people which belong to the Ids in participation var AppointmentsAndPeople = AppointmentsAndParticipations.Join ( people, a => a.PeopleId, // Similar to 1st join... p => p.Id, (a, p) => new { Appointment = a.Appointment, People = p } ); foreach (var item in AppointmentsAndPeople) { Console.WriteLine(item.Appointment.Id.ToString().PadLeft(5) + ", " + item.Appointment.Subject.PadLeft(15) + ", " + item.People.Name + " " + item.People.Surname); } Console.WriteLine("***** Group the rows *****"); // Now we want to group the rows back to Appointment-Level. We group by Appointment and People will be out elements to be sum-up var AppointmentPools = AppointmentsAndPeople.GroupBy ( key => key.Appointment, // Select the 'column' which shall be the keys group => group.People, // Select the 'column' which will be converted to a single value (like count, sum, max ..or in your case string.join()) (key, group) => new // Build the output object.. { Id = key.Id, Subject = key.Subject, Participants = string.Join(", ", group.Select(s => s.Name + " " + s.Surname)) } ); foreach (var item in AppointmentPools) { Console.WriteLine("Id: " + item.Id + ", Subject: " + item.Subject + ", Participants: " + item.Participants); } }