IQueryable <int>не содержит определения для Contains

Question

У меня проблема с linq to sql. Мой sql запрос:

  Select emp_name from employee where emp_manager_id in (Select emp_id  from employee where dept_id in 
                                                    (Select dept_id from department where dept_name='admin')
                                               )
                                               and emp_salary between
                                               (Select min_salary from salarygrades where grade='B')
                                               and 
                                               (Select max_Salary from salarygrades where grade='B')

Я пытаюсь преобразовать это в выражение linq, тогда у меня возникает проблема

var min_salary = from salarygrade in dbe.salarygrades where salarygrade.grade == "B" select salarygrade.min_Salary;
            var max_salary = from salarygrade in dbe.salarygrades where salarygrade.grade == "B" select salarygrade.max_Salary;
            var dept_id = from department in dbe.departments where department.dept_name.Contains("admin") select department.dept_id;
            var manager_id = from employee in dbe.employees where dept_id.Contains(employee.dept_id) select new { employee.emp_manager_id, employee.emp_id, employee.dept_id };


 var manager_id = from employee in dbe.employees where dept_id.Contains(employee.dept_id) select new { employee.emp_manager_id, employee.emp_id, employee.dept_id };

Iполучаю IQueryable<int> не содержит определения для методов Contains

Answer 1

Пожалуйста, добавьте using System.Linq в свои ведомости импорта

https://docs.microsoft.com/en-us/dotnet/api/system.linq.queryable.contains?view=netframework-4.8