Join fiddle

CSharp · Console

/Program.cs

using System;
using System.Collections.Generic;	
using System.Linq;

public class Program
{
	public static void Main()
	{
		var loc1 = new Location(){
			Id = 1,
			Name = "First location"
		};
		var loc2 = new Location(){
			Id = 2,
			Name = "Second location"
		};
		
		var locList = new List<Location>(){
			loc1, loc2
		};
		
		var saleT1 = new SaleTransaction(){
			Id = 1,
			LocationId = 1,
			Name = "First SaleT"
		};
		var saleT2 = new SaleTransaction(){
			Id = 2,
			LocationId = 2,
			Name = "Second SaleT"
		};
		var saleT3 = new SaleTransaction(){
			Id = 3,
			LocationId = 1,
			Name = "Third SaleT"
		};
		
		var saleList = new List<SaleTransaction>(){
			saleT1, saleT2, saleT3
		};
		
		Console.WriteLine("Join on locationId = 2");
		var locId2List = saleList.Join(locList, s => s.LocationId, l => l.Id, (s, l) => new {s.Id, s.Name, s.LocationId, locationName = l.Name})
			.Where(l => l.LocationId == 2);
		foreach(var item in locId2List){
			Console.WriteLine("\t" + item.Id + " " + item.Name + " " + item.LocationId + " " + item.locationName + "\n");
		}
	}
}

public class SaleTransaction
{
	public int Id {get;set;}
	public int LocationId {get;set;}
	public string Name {get;set;}
}

public class Location 
{
	public int Id {get;set;}
	public string Name {get;set;}
}