Can't I use two different condition at "on" in a join?

Question

Tried this :

myStructs = from MyObject s in MyObjects
            join c in Categories on s.CategoryID equals c.Item1 && s.Stars equals c.Item2
            select s;

but seems I can't wrote 2 condition at the join? Where am I wrong? On SQL this can be done as well...

Tim Schmelter · Accepted Answer · 2012-07-17T15:41:33.453

2

You need an anonymous type to join on multiple conditions/fields:

myStructs = from s in MyObjects
            join c in Categories 
            on new { s.CategoryID, s.Stars }  equals new { CategoryID = c.Item1, Stars = c.Item2 }
            select s;

edited Jul 17 '12 at 15:41

answered Jul 17 '12 at 15:36

Tim Schmelter

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It said "the type of one of the expressions in the join clause is incorrect'" – markzzz Jul 17 '12 at 15:39
@markzzz: Edited my answer, you need to use the same names in the anonymous types. – Tim Schmelter Jul 17 '12 at 15:43

Can't I use two different condition at "on" in a join?

1 Answers1