linq joins

Join In Linq

Join when using LINQ. There are no keywords defined in C#, we have to use DefaultIfEmpty() function to get the desired result.

linq simple outer joins

var query = from person in people
            join pet in pets on person.FirstName equals pet.Name
            select new { person.FirstName, person.LastName };

linq outer Joins

linq inner joins

var query = from person in people
            join pet in pets on person equals pet.Owner
            select new { OwnerName = person.FirstName, PetName = pet.Name };

linq left outer joins

var query = from person in people
             join pet in pets on person equals pet.Owner into gj
             from subpet in gj.DefaultIfEmpty()
             select new { person.FirstName, PetName = (subpet == null ? String.Empty : subpet.Name) };

linq right outer joins

var rightOuterJoin = from pet in pets
                      join person in people on pet.Name equals person.FirstName into temp
                      from person in temp.DefaultIfEmpty()
                      select new
                      {
                        PatName = pet.Name,
                        FirstName = person != null ? person.FirstName : default(string), // person.FirstName,
                        LastName = person != null ? person.LastName : default(string),
                      };

Person and Pet Class

class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

    class Pet
    {
        public string Name { get; set; }
        public Person Owner { get; set; }
    }

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