这句sql如何翻译成linq？

sql=“select Code, StudentName  from [Student]”
if(TeacherName!=""){
sql+=" ,[Teacher] where [Student].TeacherName = [Teacher] .TeacherName Where         [Teacher].TeacherName=TeacherName"
}

            var teacherName = string.Empty;
            var teachers = new List<(string Code, string TeacherName)>();
            new List<(string Code, string StudentName, string TeacherName)>()
                .Where(t => !string.IsNullOrEmpty(teacherName) && teachers.Any(g => g.TeacherName == teacherName));