How to get path alaise for the node id?

To get the path alias of any node id:

drupal_lookup_path('alias',"node/".$record->nid);

To get nid from the path alias:

drupal_lookup_path( 'source', alais_path_url);

Or we can use

Use of drupal_get_path_alias over drupal_lookup_path due to to the use of custom_url_rewrite().

drupal_get_path_alias("node/534") ;