Делаю апишку, но видает ошибку возле знака "="

Вот сам код:

[HttpPut]
            public JsonResult Put(Employee emp)
            {
                string query = @"
                        update dbo.Employee set 
                        EmployeeName = '" + emp.EmployeeName + @"'
                        ,Department = '" + emp.Department + @"'
                        ,DateOfJoining = '" + emp.DateOfJoining + @"'
                        where EmployeeId = " + emp.EmployeeId + @"
                        ";
                DataTable table = new DataTable();
                string sqlDataSource = _configuration.GetConnectionString("EmployeeAppCon");
                SqlDataReader myReader;
                using (SqlConnection myCon = new SqlConnection(sqlDataSource))
                {
                    myCon.Open();
                    using (SqlCommand myCommand = new SqlCommand(query, myCon))
                    {
                        myReader = myCommand.ExecuteReader();
                        table.Load(myReader); ;
                        myReader.Close();
                        myCon.Close();
                    }
                }
                return new JsonResult("Added successfully");
            }

[HttpPut]
        public JsonResult Put(Employee emp)
        {
            string query = @"
                    update dbo.Employee set 
                    EmployeeName = '" + emp.EmployeeName + @"'
                    ,Department = '" + emp.Department + @"'
                    ,DateOfJoining = '" + emp.DateOfJoining + @"'
                    where EmployeeId = " + emp.EmployeeId + @"
                    ";
            DataTable table = new DataTable();
            string sqlDataSource = _configuration.GetConnectionString("EmployeeAppCon");
            SqlDataReader myReader;
            using (SqlConnection myCon = new SqlConnection(sqlDataSource))
            {
                myCon.Open();
                using (SqlCommand myCommand = new SqlCommand(query, myCon))
                {
                    myReader = myCommand.ExecuteNonQuery();
                    table.Load(myReader); ;
                    myReader.Close();
                    myCon.Close();
                }
            }
            return new JsonResult("Added successfully");
        }