1.) Go to 'LearnDash LMS' on left side bar menu -> 'Settings' -> 'Delete User Statistics and User Quiz Attempts'. Check the first form section.
Only administrators has access on this page.
2.) Process of deleting records involves 2 steps:
First Step: Counting all records to be deleted using 'Check Records' button. The form has two filters: Date and Exams.
Date: Selects the to date where the record was created.
Exams: For selected exam. If this empty, it will check all records of all exams.
Second Step: Deleting all the user quiz statistics records from start to selected date using 'Delete' button that also shows a confirmation dialog box before the actual deletion.
This functionality deletes all records of the tables 'wp_wp_pro_quiz_statistic_ref' and 'wp_wp_pro_quiz_statistic' from the oldest record to selected date(from date field on the form).
Below are the sample records for both 'wp_wp_pro_quiz_statistic_ref' and 'wp_wp_pro_quiz_statistic' tables.
Sample records of 'wp_wp_pro_quiz_statistic_ref' table.
Sample records of 'wp_wp_pro_quiz_statistic' table.