I am using Opencart for my store Shop.wayanad.co.in
But in Opencart, its difficult to find who has subscribed for the newsletter and who hasn’t. Even though there are paid plugins, I am sharing a way without buying a commercial module.
Go to Phpmyadmin from your cpanel/ Direct Admin
Select the database of Opencart
Paste query into SQL window (SQL Tab)
Copy below code and run SQL query
SELECT firstname, lastname, email FROM oc_customer WHERE newsletter = '1'
In the results page that comes up, scroll to the bottom of the page to where it says ‘Query results operations’ and click on the ‘Export’ link.
Or you can select all rows by making the limit to 500 rows and then export to .csv format. This csv file can be imported to Mailchimp or Smaily or any other newsletter provider.