Question

I have a polling web application, which has a bunch of polls. There are two tables, one with poll question’s and answers, and one with people’s votes on those polls. For each user I want to provide next functionality, so that when they press a next button it will take them to a new poll that they have not answered. I don’t want to add anymore fields to the table, and I am not sure how to “save” the poll id’s for a specific user which have not been answered. This has definitely been done many times before, What are solutions/design patterns you have used?

Answer 1

Get a random poll user hasn’t answered yet:

SELECT p.poll_id FROM polls p WHERE p.poll_id NOT IN
(SELECT r.poll_id FROM poll_to_user r WHERE r.user_id = [current_user_id])
ORDER BY RAND() LIMIT 1;