I have some custom fields in my product info templates in my store. I want to create some switches so that if there is no data in the sql, the code disappears on the catalog side.

This is what I have. It correctly comments out the code if there is no data in the sql BUT it is not displaying the sql data if there is data.

Code:
<?php $product_info = $db->Execute("select jewel_ring_weight from " . TABLE_PRODUCTS . " where products_id = '" . (int)zen_db_prepare_input($_GET['products_id']) . "'");
if ($product_info->fields['jewel_ring_weight'] > 0) {
  echo '<br />';
  echo '<tr class="prodSpecItem2 prodS"><td class="prodSpec2">Weight - Band (g):</td><td>' . ($product_info->fields['jewel_band_weight'] ) . '</td></tr>';
}
?>
This is the code it is not displaying:

<td>' . ($product_info->fields['jewel_band_weight'] ) . '</td>

Is this the correct way to extract the data from the database? If not what am I doing wrong?

Thanks for helping a novice.