LINQ到實體，使用SQL不是在運營商

Question

嗨 我怎麼能寫通過LINQ

Select * From Employee where EmployeeId not in (Select EmployeeId in orders) 

Answer 1

下面的SQL查詢您可以嘗試兩種這樣的：

var query = from e in context.Employees 
      let ids = context.Orders.Select(o => o.Employee.Id) 
      where !ids.Contains(e.Id) 
      select e; 

或本：

var query = from e in context.Employees 
      where !context.Orders.Any(o => o.Empolyee.Id == e.Id) 
      select e;