Multiple JOINs

[codeline]

I've got a region-type select form where a user chooses his/her continent, and depending on the selection, a second select form is filled with country values relating to that continent. From there, depending on the country selection, a third select form is dynamically filled with regions relating to that country and continent. See the code attached:

 

<form action="" method="POST">
    <select id="continent" name="continent" style="min-width: 170px;">
        <option value="">Select Continent</option>
        <?php
        $q = "SELECT * FROM table_areaContinent";
        $r = mysql_query($q) or die(mysql_error());
        
        while($row = mysql_fetch_array($r)){
            $continent_id = $row['cont_id'];
            $continent = $row['continent'];
            
            print '<option value="' . $continent_id . '">' . $continent . '</option>' . "\n";
        }
        ?>
    </select>
    
    <br /><br />
    
    <select id="country" name="country" style="min-width: 170px;">
        <option value="">Select Country</option>
        <?php
        $q = "SELECT * FROM table_areaCountry JOIN table_areaContinent USING (cont_id)";
        $r = mysql_query($q) or die(mysql_error());
        
        while($row = mysql_fetch_array($r)){
            $country_id = $row['country_id'];
            $country = $row['country'];
            $continent_id = $row['cont_id'];
            
            print '<option value="' . $country_id . '" class="' . $continent_id . '">' . $country . '</option>' . "\n";
        }
        ?>
    </select>
    
    <br /><br />

    <select id="region" name="region" style="min-width: 170px;">
        <option value="">Select Region</option>
        <?php
        $q = "SELECT * FROM table_areaRegion JOIN table_areaCountry USING (country_id)";
        $r = mysql_query($q) or die(mysql_error());
        
        while($row = mysql_fetch_array($r)){
            $region_id = $row['region_id'];
            $region = $row['region'];
            $country_id = $row['country_id'];
            
            print '<option value="' . $region_id . '" class="' . $country_id . '">' . $region . '</option>' . "\n";
        }
        ?>    
    </select>
    
    <br /><br />
    
    <input type="submit" value="Submit" name="submit" class="submit" />
</form>

 

Now, I simply just want to echo out the Continent, Country and Region that the user selected after the form is submitted. I currently have this :

 

<?php
if(!empty($_POST['submit'])){
    $continent = $_POST['continent'];
    $country = $_POST['country'];
    $region = $_POST['region'];
    
    print '
    <b>Continent: ' . $continent . '<br />
    <b>Country: ' . $country . '<br />
    <b>Region: ' . $region . '<br />
    ';
}
?>

 

Which echoes out the ID numbers for each variable. What would be the best direction to take when pulling data from multiple tables to echo out the actual Names that the IDs are assigned to?

[codeline]

I played around and this seems to work. However, I wanted to see if there was anything wrong with going about it this way.

 

<?php

if(!empty($_POST['submit'])){

    $continent = $_POST['continent'];
    $country = $_POST['country'];
    $region = $_POST['region'];
    
    $q = "SELECT * FROM areaContinent, areaCountry, areaRegion WHERE areaRegion.region_id = '$region' AND areaCountry.country_id = '$country' AND areaContinent.cont_id = '$continent'";
    $r = mysql_query($q) or die(mysql_error());
    
    while($row = mysql_fetch_array($r)){
        $row_continent = $row['continent'];
        $row_country = $row['country'];
        $row_region = $row['region'];

        print '
        <b>Continent: ' . $row_continent . '<br />
        <b>Country: ' . $row_country . '<br />
        <b>Region: ' . $row_region . '<br />
        ';
    
    }

}

?>

[codeline]

Anyone got any advice on the above?

[rwwd]

Oh Yes!

    $continent = mysql_real_escape_string(strip_tags($_POST['continent']));
    $country = mysql_real_escape_string(strip_tags($_POST['country']));
    $region = mysql_real_escape_string(strip_tags($_POST['region']));

 

Now your $_POST information is sql safe, leaving it unsanitised is a BAD idea, seriously.

 

Rw