using EntityFrameworkCore_ConsoleApp.Models;

namespace EntityFrameworkCore_ConsoleApp
{
    public class Program
    {
        static void Main(string[] args)
        {
            using (var databaseContext = new DatabaseContext())
            {
                var invoices = databaseContext.Accounts.Join(
                        databaseContext.Invoices,
                        account => account.Id,
                        invoice => invoice.AccountId,
                        (account, invoice) => new
                        {
                            InvoiceId = invoice.Id,
                            InvoiceName = invoice.Name,
                            Created = invoice.Created,
                            Status = invoice.Status,
                            Payment = invoice.Payment,
                            AccountId = account.Id,
                            FullName = account.FullName,
                            Phone = account.Contact.Phone,
                            Address = account.Contact.Address
                        }
                    ).ToList();
                Console.WriteLine("Invoice List");
                invoices.ForEach(invoice =>
                {
                    Console.WriteLine("Invoice Id: " + invoice.InvoiceId);
                    Console.WriteLine("Invoice Name: " + invoice.InvoiceName);
                    Console.WriteLine("Created: " + invoice.Created.ToString("dd/MM/yyyy"));
                    Console.WriteLine("Status: " + invoice.Status);
                    Console.WriteLine("Payment: " + invoice.Payment);
                    Console.WriteLine("Account Id: " + invoice.AccountId);
                    Console.WriteLine("Full Name: " + invoice.FullName);
                    Console.WriteLine("Phone: " + invoice.Phone);
                    Console.WriteLine("Address: " + invoice.Address);
                    Console.WriteLine("--------------------------");
                });
            }
        }
    }
}

Output

Invoice List
Invoice Id: 1
Invoice Name: Invoice 1
Created: 20/10/2023
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
--------------------------
Invoice Id: 2
Invoice Name: Invoice 2
Created: 21/11/2022
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
--------------------------
Invoice Id: 3
Invoice Name: Invoice 3
Created: 11/04/2022
Status: Status 2
Payment: Payment 2
Account Id: 2
Full Name: Name 2
Phone: 145232
Address: Address 2
--------------------------
Invoice Id: 4
Invoice Name: Invoice 4
Created: 16/07/2021
Status: Status 2
Payment: Payment 2
Account Id: 2
Full Name: Name 2
Phone: 145232
Address: Address 2
--------------------------
Invoice Id: 5
Invoice Name: Invoice 5
Created: 25/11/2023
Status: Status 3
Payment: Payment 3
Account Id: 3
Full Name: Name 3
Phone: 232343
Address: Address 3
--------------------------
Invoice Id: 6
Invoice Name: Invoice 6
Created: 18/11/2023
Status: Status 3
Payment: Payment 3
Account Id: 3
Full Name: Name 3
Phone: 232343
Address: Address 3
--------------------------

You can use combination of Join and Where method as below:

using EntityFrameworkCore_ConsoleApp.Models;

namespace EntityFrameworkCore_ConsoleApp
{
    public class Program
    {
        static void Main(string[] args)
        {
            using (var databaseContext = new DatabaseContext())
            {
                var invoices = databaseContext.Accounts.Join(
                        databaseContext.Invoices,
                        account => account.Id,
                        invoice => invoice.AccountId,
                        (account, invoice) => new
                        {
                            InvoiceId = invoice.Id,
                            InvoiceName = invoice.Name,
                            Created = invoice.Created,
                            Status = invoice.Status,
                            Payment = invoice.Payment,
                            AccountId = account.Id,
                            FullName = account.FullName,
                            Phone = account.Contact.Phone,
                            Address = account.Contact.Address
                        }
                    ).Where(invoice => invoice.Status == "Status 1").ToList();
                Console.WriteLine("Invoice List");
                invoices.ForEach(invoice =>
                {
                    Console.WriteLine("Invoice Id: " + invoice.InvoiceId);
                    Console.WriteLine("Invoice Name: " + invoice.InvoiceName);
                    Console.WriteLine("Created: " + invoice.Created.ToString("dd/MM/yyyy"));
                    Console.WriteLine("Status: " + invoice.Status);
                    Console.WriteLine("Payment: " + invoice.Payment);
                    Console.WriteLine("Account Id: " + invoice.AccountId);
                    Console.WriteLine("Full Name: " + invoice.FullName);
                    Console.WriteLine("Phone: " + invoice.Phone);
                    Console.WriteLine("Address: " + invoice.Address);
                    Console.WriteLine("--------------------------");
                });
            }
        }
    }
}

Output

Invoice List
Invoice Id: 1
Invoice Name: Invoice 1
Created: 20/10/2023
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
--------------------------
Invoice Id: 2
Invoice Name: Invoice 2
Created: 21/11/2022
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
--------------------------

You can also join multiple tables as below:

using EntityFrameworkCore_ConsoleApp.Models;

namespace EntityFrameworkCore_ConsoleApp
{
    public class Program
    {
        static void Main(string[] args)
        {
            using (var databaseContext = new DatabaseContext())
            {
                var invoices = databaseContext.Accounts.Join(
                        databaseContext.Invoices,
                        account => account.Id,
                        invoice => invoice.AccountId,
                        (account, invoice) => new
                        {
                            InvoiceId = invoice.Id,
                            InvoiceName = invoice.Name,
                            Created = invoice.Created,
                            Status = invoice.Status,
                            Payment = invoice.Payment,
                            AccountId = account.Id,
                            FullName = account.FullName,
                            Phone = account.Contact.Phone,
                            Address = account.Contact.Address
                        }
                    )
                    .Join(
                        databaseContext.InvoiceDetails,
                        invoiceJoinAccount => invoiceJoinAccount.InvoiceId,
                        invoiceDetails => invoiceDetails.InvoiceId,
                        (invoiceJoinAccount, invoiceDetails) => new
                        {
                            InvoiceJoinAccount = invoiceJoinAccount,
                            InvoiceDetails = invoiceDetails
                        }
                    )
                    .Where(invoice => invoice.InvoiceJoinAccount.Status == "Status 1")
                    .ToList();
                Console.WriteLine("Invoice List");
                invoices.ForEach(invoice =>
                {
                    Console.WriteLine("Invoice Id: " + invoice.InvoiceJoinAccount.InvoiceId);
                    Console.WriteLine("Invoice Name: " + invoice.InvoiceJoinAccount.InvoiceName);
                    Console.WriteLine("Created: " + invoice.InvoiceJoinAccount.Created.ToString("dd/MM/yyyy"));
                    Console.WriteLine("Status: " + invoice.InvoiceJoinAccount.Status);
                    Console.WriteLine("Payment: " + invoice.InvoiceJoinAccount.Payment);
                    Console.WriteLine("Account Id: " + invoice.InvoiceJoinAccount.AccountId);
                    Console.WriteLine("Full Name: " + invoice.InvoiceJoinAccount.FullName);
                    Console.WriteLine("Phone: " + invoice.InvoiceJoinAccount.Phone);
                    Console.WriteLine("Address: " + invoice.InvoiceJoinAccount.Address);
                    Console.WriteLine("Product Id: " + invoice.InvoiceDetails.ProductId);
                    Console.WriteLine("Price: " + invoice.InvoiceDetails.Price);
                    Console.WriteLine("Quantity: " + invoice.InvoiceDetails.Quantity);
                    Console.WriteLine("--------------------------");
                });
            }
        }
    }
}

Output

Invoice List
Invoice Id: 1
Invoice Name: Invoice 1
Created: 20/10/2023
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
Product Id: 9
Price: 4.5
Quantity: 20
--------------------------
Invoice Id: 1
Invoice Name: Invoice 1
Created: 20/10/2023
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
Product Id: 10
Price: 11
Quantity: 21
--------------------------
Invoice Id: 1
Invoice Name: Invoice 1
Created: 20/10/2023
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
Product Id: 11
Price: 20
Quantity: 3
--------------------------
Invoice Id: 2
Invoice Name: Invoice 2
Created: 21/11/2022
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
Product Id: 9
Price: 4.5
Quantity: 20
--------------------------
Invoice Id: 2
Invoice Name: Invoice 2
Created: 21/11/2022
Status: Status 1
Payment: Payment 1
Account Id: 1
Full Name: Name 1
Phone: 123456
Address: Address 1
Product Id: 13
Price: 6
Quantity: 11
--------------------------

The post Join Method in LINQ MeThods in Entity Framework Core appeared first on OctopusCodes.