<?php
$username="User";
$password="Pass";
$database="database";
mysql_connect('localhost',$username,$password) or trigger_error( mysql_error() . " Unable to connect to database");
mysql_select_db($database) or trigger_error( mysql_error() . " Unable to select database");
?>


<?php
$query = mysql_query('SHOW COLUMNS FROM `WorkActivity`');
if (mysql_num_rows($query) > 0) {
    echo '<select name="" id="">';
    foreach (mysql_fetch_assoc($query) as $row) {
        if ($row['Field'] !== 'ID') echo '<option value="' . $row['Field'] . '">' . $row['Field'] . '</option>' . "\n";
    }
    echo '</select>';
} else {
    echo 'Nothing in database';
}

?>