Local sequence cannot be used in LINQ to SQL implementation of query operators except the Contains() operator

Question

I am using LINQ in my project and my code is:

var SE = from c in Shop.Sections
                    join c1 in obj.SectionObjects on c.SectionId equals c1.Sec         


        

Answer 1

This should work and be done on the database side (using IN), rather than in memory:

var SE = from c in Shop.Sections 
        where obj.SectionObjects.Select(z => z.SectionId).Contains(c.SectionId)
        select c; 

L2S Profiler is very helpful for these kinds of things - you can compare the different SQL being generated by my solution and other solutions.