Here, i am going to post simple Magento tweak. That is how to get the product URL by product id. Sometimes we only have the product id, That’s enough to get all the product instance.So using below code we can get the product url by id.

  $my_product = Mage::getModel('catalog/product')->load($product_id); 
  $my_product_url = $my_product->getProductUrl();  

Hope it helps someone.