Question

I have a web app which users login to it.
Every time a specific user logs in, I store the login datetime in a MySQL db:

(yyyy-mm-dd hh-mm-ss) 

Each record in the db has a user_identifier and last_login_datetime.
However, I want to make sure that users can only login once a day.
I was thinking about comparing the time function in PHP to the datetime I have in the DB and see if the user was already logged on today.
If the user was logged on today, I’ll kick him out.

How do I compare the record in the DB to the time function in PHP to see if the user was logged in already?

Thanks!

Answer 1

You might add something like this to conditions of the SELECT to validate a user’s credentials when they login

... (AND DAY(last_login_datetime) != DAY(NOW()) OR MONTH(last_login_datetime) != MONTH(NOW()) OR YEAR(last_login_datetime) != YEAR(NOW()))

If the day, month, or year do not match today’s day, month, and year, the select will return the user (assuming the other credentials/conditions are valid). If no result is returned, the user’s credentials were incorrect or the user has already logged in today – either way they should not be allowed to login according to your requirements.