php - php mysqli 语句中绑定参数的错误

Question

$Statement= mysqli_prepare( $this->mysqli,'UPDATE empData SET Name=?, 
                            Email=?,
                            PhoneNumber = ?, 
                            AddressLine1 =?,          
                            AddressLine2 =?, 
                            CityID =?, 
                            Zip = ?, 
                            ModifiedOn = now()
                            WHERE id = ?');
mysqli_stmt_bind_param($Statement, 'sssssisi', trim($name), 
                        trim($email), 
                        trim(phnumber), 
                        trim(address1), 
                        trim(address2), 
                        $city=2, 
                        trim($zipcode), 
                        $id);
mysqli_stmt_execute($Statement);

该查询在服务器严格标准上给了我一个错误： value pass by reference on line where I used trim and$city=2

在本地它运行良好，但在服务器上它给了我上述错误？

还有其他方法可以使用 mysqli 编写这些查询吗？