IQueryable<> from stored procedure (entity framework)

You can use a project I created called LinqToAnything which lets you take a non-queryable data access method and turn it into an IQueryable.

I've got a blog post here on how to use it.

You can't do what you're trying to do, for the same reason that you can't put a stored procedure in a FROM clause of a SELECT query - SQL isn't built to support this kind of operation.

Could you put the logic you want into a view instead of a stored procedure?