How do I perform a Left Outer Join in Linq?

Question

I am new to Linq, and I need to convert this query to a left outer join between DocumentStores and Orders, as not all documents are related to an order:

    var documents=(from d in _dataContextOrders .DocumentStores 
                           join o in _dataContextOrders.Orders on d.OrderID equals o.ID
                           join t in _dataContextOrders .DocumentTypes on d.DocumentType equals t.DocTypeID
                       select new
                           {
                               d.ID,
                               o.PORef ,
                               t.DocTypeDescription,
                               d.Name,
                               d.ContentType
                           }).ToList();

How do I achieve this?

You may check this article i've written: http://www.experts-exchange.com/Programming/Languages/.NET/A_11369-Joining-in-LINQ.html — Giannis Paraskevopoulos, Jul 25 '14 at 13:38

score 1 · Answer 1 · answered Jul 25 '14 at 13:37

1

from a in dataContext.<tableA>
join _b in dataContext.<tableB> on a.id equals _b.aid into _b
from b in _b.DefaultIfEmpty()
select <whatyouwanttoselect>

b will be null, if the join on the ids fails

answered Jul 25 '14 at 13:37

schlonzo

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How do I perform a Left Outer Join in Linq?

1 Answers1