how to create report with total discount prices?

Hi,

I don't see a way to do these in the backend.
A custom plugin would be needed.
If you can write the MySQL query to get the data in PHPMyAdmin, then it's just a matter of implementing a plugin similar to the email history plugin, which adds the menu Customers>Emails history to HikaShop's backend, but instead of displaying a listing of the entries in the email_log table which it fills automatically when an email is sent, it would run your MySQL query to get the data, and then in the view file, you would just have to display the data in an HTML table.
You can check the code of the email history plugin in the folder plugins/hikashop/email_history on your website.

Hi,

If you activate the "debug system" setting in the Joomla configuration, you'll see all the MySQL queries run on the current page on each page of your backend and frontend.
Just unfold the MySQL queries area and look for hikashop_order when you're looking at the page where the report is displayed and you'll get the MySQL query the report uses.