CODEWITHSUNDEEP
c#linq
frenchie
frenchie

Reputation: 51927

selecting based on null

I'm building a dynamic query and doing a join between 2 entities: the query being built and a table.

I have:

var TheQuery = ...;

TheQuery = from x in TheQuery
           join c in MyDataContext.TheTable on
           x.ID equals c.ID
           where "there's no matching element in TheTable"
           select x

Thanks for your suggestions.

Upvotes: 0

Views: 58

Answers (1)

BrokenGlass
BrokenGlass

Reputation: 160862

To do a Left outer join with LINQ you have to use join .. into and DefaultIfEmpty():

TheQuery = from x in TheQuery
           join c in MyDataContext.TheTable on x.ID equals c.ID into outer
           from o in outer.DefaultIfEmpty()
           where o == null
           select x

Upvotes: 2

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