Return the id of an element using Linq

Question

I have a function that should return the Id of the element passed in parameters, like :

public static Int32 getIdByName(string name)
{
    var query = from student in DataAccess.getInstance.StudentSet
                where student.FirstName.Equals(name)
                select student;

    return toto;
}

I don't know how to convert the result toto to an Int32 and return it !!

Answer 1

return DataAccess.getInstance.StudentSet.Last(s => s.FirstName == name).Id;

Answer 2

public static Int32 getIdByName(string name)
{
    var query = from student in DataAccess.getInstance.StudentSet
                where student.FirstName.Equals(name)
                select student.Id;

    return query.First();
}