Delete old columns from table using hook update I need to delete some old columns of existing table. How to do it using hook_update or Is there some other way to delete old columns in .install file .

Thanks
You can use function db_drop_field()

/**
 * Implements hook_update_N().
 */
function mymodule_update_7001() {
  db_drop_field('my_table', 'my_column');
}