Question

I’ve been at this for hours and i have gotten a slight break through, however i am at a stand still at the moment. I have a SQL Database that store vehicle information, such as make, model and year. What i want to do is allow users to modify the query and only display specific results.

I understand how to display all the records at once but what i want to add is when the user selects say for example the make as “Toyota” i want only that specific make to appear. I did reach some where in this, by using this code:

<form method="post" action=""> 
 <div id="search_query" >
     Make 
    <select name="make" size="0">
    <option value="honda">Honda</option>
  <option value="toyota">Toyota</option>
  <option value="nissan">Nissan</option>
    </select>

     <input type="submit" name="submit" value="submit">

 </div>
 </form>     

<?php

    $db_con = mysql_connect('localhost', 'root', '');

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

    mysql_select_db('my_db', $db_con);

    $make = mysql_real_escape_string($_POST['make']);

    $sql = sprintf("SELECT * FROM chjadb_vehicles WHERE v_make= '$make' ");


    $result = mysql_query($sql);


    echo "<table width= 970 border=1>
         <tr>
           <th width='120' scope='col'>Image</th>
           <th width='170' scope='col'>Details</th>
           <th width='185' scope='col'>Seller</th>
           <th width='126' scope='col'>Price</th>
         </tr>";
    while($row = mysql_fetch_array($result))
      { 
         echo "<tr>";
           echo "<td> <img src=" .$row['v_image']. " width =200 height = 130>" . "</td>";
           echo "<td>". $row['v_year'] . "&nbsp;" . $row['v_make'] . "&nbsp;". $row['v_model'] . "&nbsp;". $row['b_type']. "</td>";
           echo "<td>". $row['user_id'] ."</td>";
           echo "<td>". $row['v_price'] ."</td>";
         echo "</tr>";
      }
       echo "</table>";

     mysql_close($db_con);
    ?>

however when i run the page initially i get this error: “Notice: Undefined index: make in C:\xampp\htdocs\carhuntja.com\buy_a_car.php on line 62”

i did some research and realized that this was happening because i had no make value set, what i wish to do here is at the start of going to that page i want all vehicles to be displayed.

Answer 1

The problem is that the query is being sent before the user chooses a make. To fix this, you need check that the user has actually submitted the form by enveloping your PHP code in if(isset($_POST['submit'])) (“submit” is used because that is the name of your submit button).

//place connection code here (do not query the database yet)

if(isset($_POST['submit']))
{
   //all of the database retrieval code
}
else
{
  $query_makes = "SELECT v_make FROM chjadb_vehicles";
  $result_makes = mysqli_query($query_makes);
  echo "Please choose a make."
  //echo opening select tag
  while($row = mysql_fetch_array($result_makes))
  {
     //echo each option tag
  }
  //echo ending select tag
}

Also, you are missing a slash in the self-contained input tag.
Finally, you should use MySQLi functions because MySQL functions are deprecated in PHP.