Можете так:
$oShop = $Shop_Controller_Show->getEntity();
$oShop_Item_Tags = Core_Entity::factory('Tag');
$oShop_Item_Tags->queryBuilder()
->select(array('COUNT(tag_id)', 'count'), 'tags.*')
->join('tag_shop_items', 'tag_shop_items.tag_id', '=', 'tags.id')
->join('shop_items', 'tag_shop_items.shop_item_id', '=', 'shop_items.id')
->where('shop_items.shop_id', '=', $oShop->id)
->where('shop_items.deleted', '=', 0)
->groupBy('tag_shop_items.tag_id')
->having('count', '>', 0)
->orderBy('tags.name', 'ASC');
$aShop_Item_Tags = $oShop_Item_Tags->findAll(FALSE);
$Shop_Controller_Show->addEntities($aShop_Item_Tags);