too long

I have a mySQL table named businesses with 4 columns.

name, url, description, category

I am trying to have the entire directory display on a page under each corresponding category name. Is there a better way to do this than what I have so far? I would like to keep all data in one table rather than having a table for each category.

<?php

$con = mysql_connect('localhost','username','password')
    or die('Could not connect: ' . mysql_error());
mysql_select_db('relicc_dogedir')
    or die('Could not select database');

$result = mysql_query("SELECT * FROM businesses ORDER BY category",$con);

$column = array();
    while($row = mysql_fetch_array($result))
    {
            $column[] = $row['category'];
    }
    $merged_column = array_unique($column);
    $refined_categories = array_values($merged_column);

    foreach ($refined_categories as &$refined_category)
    { ?>
        <h3><?php echo $refined_category;?></h3><?php 

        //Display sorted business names with corresponding category


    }

mysql_close($con);
?>

First, you should know that the mysql extension is deprecated, you should use MySQLi or PDO_MySQL.

You could first retrieve the categories, and then foreach categories retrieve the corresponding businesses.

    try
    {
        $dbh = new PDO('mysql:host=localhost;dbname=YOURDB', 'USERNAME', 'PASSWORD');
    }
    catch(PDOException $e)
    {
        echo $e->getMessage();
        die;
    }

    $stmt = $dbh->query('SELECT category FROM businesses GROUP BY category');
    $stmt->setFetchMode(PDO::FETCH_ASSOC);

    $categories = $stmt->fetchAll();
    foreach ($categories as $category)
    {
        echo '<h3>'.$category['category'].'</h3>';

        $stmt = $dbh->prepare('SELECT * FROM businesses WHERE category = :categoryName');
        $stmt->bindParam(':categoryName', $category['category'], PDO::PARAM_STR);
        $stmt->execute();
        $businesses = $stmt->fetchAll();

        foreach ($businesses as $business)
        {
            echo $business['name'];
            echo '<br />';
        }
    }

You could group your data by category in PHP.

...
$result = mysql_query("SELECT * FROM businesses ORDER BY category, name", $con);

$data = array();
while($row = mysql_fetch_array($result))
{
    $data[$row['category']][] = $row;
}

foreach($data as $categoryName => $categoryData) {
    echo '<h3>' . $categoryName . '</h3>';
    foreach ($categoryData as $business) {
        // display sorted business data using business
        // echo $business['name'];
    }
}
...