Appending extra columns to Views table
There are multiple ways you can add an extra column or a field to each row of your views output. And you can choose what is best for your use case.

For a Drupal 7 site you can use - 


https://drupal.org/project/computed_field
https://drupal.org/project/views_php
for extra fields in plain text, you can refer this answer. 


If you need to pass any kind of dynamic context to your custom extra field, say a node id, there are multiple ways to do that too.