Where clause in LINQ Query with Entity Framework

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

假设“ Payments不是“ Students的字段，而是代表与该“ Student相关的“ Payment项集合的属性，请尝试以下查询：

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