Table structure of active members for 4 years in sql - mysql

Question

I am working on an achievement system and the users can unlock a badge when they have been active on the site for 4 years.
I tried to store each time a user in logged in but it's not really a good idea.
So my question is, how the table structure should be if I want to know if the user was active for 4 years?

Answer 1

It depends on what you mean by active, but if you mean that four years has elapsed since they first logged on, registered etc. then you just need a date field to store the account setup / logon etc. Then when they logon you can test to see if four years has past since that date and insert a badge accordingly.

Answer 2

You can save the last consecutive log in and the first log in. That's just two columns. Every time a user logs in, you can check if he logged in the day before. If yes, then update that column. If not then update the first log in because that's when the 4 year period will begin again. Let me know if that makes sense or if you need examples to help with understanding the thought process.

Answer 3

That is too generic a question to provide an full solution. By active for 4 years it sounds like you will need to track their actions. So perhaps some sort of transaction or history table that links their userid with a datetime plus actions performed.
Then you just have to define what "active" means such as having performed specific actions at least once per week, etc.
EDIT
First off I am a SQL Server developer, but have attempted to convert this to MySQL syntax for you.
~ = primay keys to ensure uniqueness & good performance
User table
~ UserID unique user id - could be an Identity, GUID or similar field
UserName unique user name
anything else you want to track such as First Name, Last Name, etc
UserAction table
~ UserID link to User table
~ ActionType number indicating what the user performed
1 = login
add in other types in the future if you ever want to track anything else
~ ActionDate datetime of the action
anything else that you may want to track such as the duration or end date (in this case that would be them logging out)
Database systems are designed to hold lots of data so you shouldn't have to worry too much about that unless space is a factor. You can always delete any data that is older than 4 or 5 years if you like.
Normally I would just use a CTE (common table expression) but apparently they won't be available until MySQL 8.0 [https://www.mysql.com/why-mysql/presentations/mysql-80-common-table-expressions/]
So instead here is another method. It assumes that you want a login within each given year. i.e. at least one login from 2017, one from 2016, 2015 & 2014. If instead you wanted at least one login going back 1 year from today and so on then we will need to modify this query.
-- this will return the number of years with at least one login, going as far back as 4 years
SELECT COUNT(1) AS NumberOfYearsWithLogin
FROM (
SELECT YEAR(CURDATE()) - YEAR(ActionDate) AS NumberOfYearsAgo
FROM UserAction
WHERE UserID = 123 -- put user of interest here
AND ActionType = 1 -- login
AND YEAR(CURDATE()) - YEAR(ActionDate) < 4 -- check the last 4 years
GROUP BY YEAR(CURDATE()) - YEAR(ActionDate) -- group by year number with today's year as number 0
) A
;