Question

I am trying to filter a LINQ query, but it’s not accepting my where clause and I have no idea what kind of Lambda function to use.

This is what I want, but this throws an error.

var query = from s in _db.Students where s.Payments == null orderby s.LastName select s;

Answer 1

Assuming that Payments is not a field of Students, but rather a property representing a collection of Payment items related to this Student, try this query instead:

var query = from s in _db.Students where !s.Payments.Any() orderby s.LastName select s;