I have a basic karma/rep system that awards users based on their activities (questions, answers, etc..). I want to have user ranks (title) based on their points. Different ranks have different limitations and grant powers.
ranks table
id rankname points questions_per_day
1 beginner 150 10
2 advanced 300 30
I’m not sure if I need to have a lower and upper limit, but for the sake of simplicity I have only left a max points limit, that is, a user below 150 is a ‘beginner’ and below or higher than 300, he’s an ‘advanced’.
For example, Bob with 157 points would have an ‘advanced’ tag displayed by his username.
How can I determine and display the rank/title of an user? Do I loop through each row and compare values?
What problems might arise if I scale this to thousands of users having their rank calculated this way? Surely it will tax the system to query and loop each time a user’s rank is requested, no?
You could better cache the rank and the score. If a user’s score only changes when they do certain activities, you can put a trigger on that activity. When the score changes, you can recalculate the rank and save it in the users record. That way, retreiving the rank is trivial, you only need to calculate it when the score changes.
You can get the matching rank id like this; query the rank that is closest (but below or equal to) the user schore. Store this rank id in the user’s record.
I added the pseudovariable {USERSCORE} because I don’t know if you use parameters or any other way to enter values in a query.