csharp

csharp-linq

Linq

FullOuterJoin

method 방식으로는 한번에 가능

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static void Main(string[] args)
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{
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    var ax = new[] { 
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        new { id = 1, name = "John" },
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        new { id = 2, name = "Sue" } };
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    var bx = new[] { 
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        new { id = 1, surname = "Doe" },
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        new { id = 3, surname = "Smith" } };
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    ax.FullOuterJoin(bx, a => a.id, b => b.id, (a, b, id) => new {a, b})
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        .ToList().ForEach(Console.WriteLine);
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}

query 방식으로는 union method로 가능

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var firstNames = new[]
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{
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    new { ID = 1, Name = "John" },
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    new { ID = 2, Name = "Sue" },
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};
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var lastNames = new[]
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{
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    new { ID = 1, Name = "Doe" },
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    new { ID = 3, Name = "Smith" },
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};
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var leftOuterJoin = from first in firstNames
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                    join last in lastNames
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                    on first.ID equals last.ID
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                    into temp
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                    from last in temp.DefaultIfEmpty(new { first.ID, Name = default(string) })
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                    select new
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                    {
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                        first.ID,
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                        FirstName = first.Name,
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                        LastName = last.Name,
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                    };
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var rightOuterJoin = from last in lastNames
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                     join first in firstNames
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                     on last.ID equals first.ID
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                     into temp
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                     from first in temp.DefaultIfEmpty(new { last.ID, Name = default(string) })
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                     select new
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                     {
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                         last.ID,
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                         FirstName = first.Name,
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                         LastName = last.Name,
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                     };
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var fullOuterJoin = leftOuterJoin.Union(rightOuterJoin);
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