Group Join

Jasurbek Xasanboyev

INNER JOIN orqali to’plamlarni ulashda bizga kerakli qismlarni ajratib olib yangi to’plam hosil qilar edik. GROUP JOIN da esa avvalgidek bir xil qism bo’yicha qo’shadi lekin hamma parametrlar ko’chib o’tadi.

Method Syntax:

class Program
{
    static void Main(string[] args)
    {
        var students = new List<Student>()
    {
        new Student() { Id = 1, Name = "Jasurbek", AddressId = 1},
        new Student() { Id = 2, Name = "Xondamir", AddressId = 1},
        new Student() { Id = 3, Name = "Shoxruh", AddressId = 3},
        new Student() { Id = 4, Name = "Shaxzod", AddressId = 4},
        new Student() { Id = 5, Name = "Abdulloh", AddressId = 2}
    };
        var addresses = new List<Address>()
    {
        new Address() {Id = 1, AddressLine = "Line 1"},
        new Address() {Id = 2, AddressLine = "Line 2"},
        new Address() {Id = 3, AddressLine = "Line 3"},
        new Address() {Id = 4, AddressLine = "Line 4"},
    };
        var MethodSyntax = addresses.GroupJoin(students, address => address.Id, 
        student => student.AddressId, (address, student) => new { address, student}).ToList();
        foreach (var item in MethodSyntax)
        {
            Console.WriteLine($"Line: {item.address.AddressLine}");
            foreach (var item2 in item.student)
            {
                Console.WriteLine($"Name: {item2.Name}");
            }
        }
        /*OUTPUT:   Line: Line 1
                    Name: Jasurbek
                    Name: Xondamir
                    Line: Line 2
                    Name: Abdulloh
                    Line: Line 3
                    Name: Shoxruh
                    Line: Line 4
                    Name: Shaxzod  */
    }
}
class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int AddressId { get; set; }
}
class Address
{
    public int Id { get; set; }
    public string AddressLine { get; set; }
}

Query Syntax

class Program
{
    static void Main(string[] args)
    {
        var students = new List<Student>()
    {
        new Student() { Id = 1, Name = "Jasurbek", AddressId = 1},
        new Student() { Id = 2, Name = "Xondamir", AddressId = 1},
        new Student() { Id = 3, Name = "Shoxruh", AddressId = 3},
        new Student() { Id = 4, Name = "Shaxzod", AddressId = 4},
        new Student() { Id = 5, Name = "Abdulloh", AddressId = 2}
    };
        var addresses = new List<Address>()
    {
        new Address() {Id = 1, AddressLine = "Line 1"},
        new Address() {Id = 2, AddressLine = "Line 2"},
        new Address() {Id = 3, AddressLine = "Line 3"},
        new Address() {Id = 4, AddressLine = "Line 4"},
    };
        var QueerySyntax = from line in addresses
                            join std in students on
                            line.Id equals std.AddressId into stdGroup
                            select new { line, stdGroup};
        foreach (var item in QueerySyntax)
        {
            Console.WriteLine($"Line: {item.line.AddressLine}");
            foreach (var item2 in item.stdGroup)
            {
                Console.WriteLine($"Name: {item2.Name}");
            }
        }
        /*OUTPUT:   Line: Line 1
                    Name: Jasurbek
                    Name: Xondamir
                    Line: Line 2
                    Name: Abdulloh
                    Line: Line 3
                    Name: Shoxruh
                    Line: Line 4
                    Name: Shaxzod  */
    }
}
class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int AddressId { get; set; }
}
class Address
{
    public int Id { get; set; }
    public string AddressLine { get; set; }
}