Join orders with customers — C# Programming

Problem

LINQ join: match orders to customer names.

Hints

join ... on ... equals ...

Your practice code

Ready — edit the code above and click Run.

Solution

using System;
using System.Linq;

class Program
{
    static void Main()
    {
        var customers = new[] { new { Id = 1, Name = "Ali" }, new { Id = 2, Name = "Sara" } };
        var orders = new[] { new { CustomerId = 1, Amount = 100 }, new { CustomerId = 2, Amount = 200 } };
        var result = from o in orders
                     join c in customers on o.CustomerId equals c.Id
                     select $"{c.Name}: {o.Amount}";
        Console.WriteLine(string.Join("\n", result));
    }
}

Try solving on your own first, then reveal the official answer.

Explanation

Query syntax join maps to SQL INNER JOIN—common in EF Core interview questions.