database query in joomla 2.5 virtuemart

Question

I wrote the following code to get virtuemart category id with name "app" from database. but its not displaying anything.please help. I use joomla 2.5 and latest version of virtuemart

$db =&  JFactory::getDBO();
$query = $db->getQuery(true);
$query->select('virtuemart_category_id');
$query->from('#__virtuemart_categories_en_gb'); 
$query->where('category_name = "app" ');   //put your condition here    
$db->setQuery($query);
$o= $db->loadObjectList();
echo $o[0]->virtuemart_category_id;

my database table prefix is nyhar_ . I wrote the above code in category view page and it doesn't show anything.

Answer 1

Try this:

$db = JFactory::getDBO();
$query = $db->getQuery(true);
$query->select('*');
$query->from('#__virtuemart_categories_en_gb'); 
$query->where('category_name = "app" ');   
$db->setQuery($query);
$o= $db->loadResult();
echo $o;

To select an id value, you can use $query->select('virtuemart_category_id');