如果不为空，则将值插入数据库；如果为空，则将值设置为“ null”

Question

I'm new to mysql. so my problem is I want to set the $status in database to 'IN PROCESS' if the subject field is not empty. and if the subject is empty, the status will set to empty. here is my code, when i run it, nothing happen to the status. Thanks!

<?php
    if(isset($_POST['submit']))
     {
         $dbhost = 'localhost';
         $dbuser = 'root';
         $dbpass = '';
         $conn = mysql_connect($dbhost, $dbuser, $dbpass);

         mysql_select_db('course');

         if(! $conn )
         {
         die('Could not connect: ' . mysql_error());
         }

         $code= $_POST['code'];
         $subject= $_POST['subject'];
         $status= $_POST['status'];

         $sql = "INSERT INTO form(code,subject,status)
         VALUES('$code','$subject','$status')";

         $retval = mysql_query( $sql, $conn );

         if(!empty($_POST['subject'])) {
                $status = 'IN PROCESS';
            }      
            else $status = 'null';

         if(! $retval )
         {
         die('Could not enter data: ' . mysql_error());
         }

         else
         {
             ?>
             <div class="alert alert-success">
               <strong>Success!</strong> .
             </div>
             <?php
         }


         mysql_close($conn);
      }
 ?>

Answer 1

Try to put Insert statement after your if condition . because the value of the $status has already insert before the condition.

<?php
        if(isset($_POST['submit']))
         {
             $dbhost = 'localhost';
             $dbuser = 'root';
             $dbpass = '';
             $conn = mysql_connect($dbhost, $dbuser, $dbpass);

             mysql_select_db('course');

             if(! $conn )
             {
             die('Could not connect: ' . mysql_error());
             }

             $code= $_POST['code'];
             $subject= $_POST['subject'];
             $status= $_POST['status'];

             if(!empty($_POST['subject'])) {
                    $status = 'IN PROCESS';
                }      
                else $status = 'null'; 
             //put it here
             $sql = "INSERT INTO form(code,subject,status)
             VALUES('$code','$subject','$status')";

             $retval = mysql_query( $sql, $conn );

             if(! $retval )
             {
             die('Could not enter data: ' . mysql_error());
             }

             else
             {
                 ?>
                 <div class="alert alert-success">
                   <strong>Success!</strong> .
                 </div>
                 <?php
             }


             mysql_close($conn);
          }
     ?>

Answer 2

set

if(!empty($_POST['subject'])) {
    $status = 'IN PROCESS';
}      
else $status = 'null';

before your query

$sql = "INSERT INTO form(code,subject,status)
     VALUES('$code','$subject','$status')";