Magento: How to Check if the SKU is Exist?

Check if the SKU is Exist ?

<?php
       $sku = "Your Product Sku ";
       $id = Mage::getModel('catalog/product')->getIdBySku($sku);
       if($id){
              echo "SKU {$sku} exists";
       }
       else{
           echo "SKU {$sku} does not exist";
       }
?>

When this code will useful.

• When you import magento products via code then this code is very useful.
• If you want to load product via sku then this is very useful.
• if you want to update any particular product via code then also this is useful.