mysql检查字段是否为null

如果orderstatus的字段为null，我将尝试创建一个默认值，返回给用户"正在处理"，如果不为null，则返回给用户字段内容。

我做了第二部分，但如果字段为空，我无法获得代码的默认值

<div id="par3" class="box">    
<div class="container">
<center>
    <div class="boxhead"><div id="heads">Forgot Password</div></div><br>
        <div class="text">
            <form action="" method="POST">
                    Order ID:
                    <input type="text" name="orderid" class="input" id="form-controls" placeholder="Your OrderID" AutoComplete="off">
                    <br /><br />
                     <input type="submit" name="submit"  class="btn btn-warning" value="Recover">
                          <?php
                            if( isset($_POST['submit'])) {
                            $orderid=$_POST['orderid'];
                            $orderid = mysql_real_escape_string($orderid);
                            ################################################
                            $checkname = "SELECT * FROM neworder WHERE ID='".$orderid."'";
                            if(mysql_num_rows(mysql_query($checkname)) < 1 )
                            { $errors .= '<script>$.jGrowl("<b><u>Recover Failed</u></b><br>Username not found!", { theme:  "error",speed:  "fast",});</script>';   }
                            ################################################
                            ################################################
                            ################################################
                            if(empty($orderid))
                            { $errors .= '<script>$.jGrowl("<b><u>Recover Failed</u></b><br>All of fields are required.", { theme:  "error",speed:  "fast",});</script>'; }
                            ################################################
                            ################################################
                            if(!empty($errors))
                            { echo "<div align='center'>".nl2br($errors)."</div>"; }
                            else {
                            $success=mysql_query("SELECT * FROM neworder WHERE ID='".$orderid."'");
            $success1=SELECT IF(orderstatus IS NULL or orderstatus = '', 'empty', orderstatus ) as orderstatus 
from neworder;

                            }

                            if($success || $success1){
                            echo "Password recovered successfully ! <br />";
                            while($row = mysql_fetch_array( $success )){
                            $orderstatus=$row['orderstatus'];
                            echo "Order Status: <font style='text-shadow: 0 0 15px rgb(153, 204, 0); color: rgb(153, 204, 0);'>".$orderstatus."</font> <br />";
                            }
                            }
                            }
                          ?>
                </form>
        </div>
        </div>
        </center>
    <div class="boxfooter"></div>
</div>

任何人都告诉我应该使用她有什么乐趣，并且适合该代码，谢谢