Laravel where 子句基于数据库中值的条件

Question

I am building an event reminder page where people can set a reminder for certain events. There is an option for the user to set the amount of time before they need to be notified. It is stored in notification_time and notification_unit . notification_time keeps track of the time before they want to be notified and notification_unit keeps track of the PHP date format in which they selected the time, eg. i for minutes, H for hours.

Eg. notification_time - 2 and notification_unit - H means they need to be notified 2 hours before.

I have Cron jobs running in the background for handling the notification. This function is being hit once every minute.

Reminder::where(function ($query) {
    $query->where('event_time', '>=', now()->subMinutes(Carbon::createFromFormat('i', 60)->diffInMinutes() - 1)->format('H:i:s'));
    $query->where('event_time', '<=', now()->subMinutes(Carbon::createFromFormat('i', 60)->diffInMinutes())->format('H:i:s'));
})

In this function, I am hard coding the 'i', 60 while it should be fetched from the database. event_time is also part of the same table

The table looks something like this -

id event_time ... notification_unit notification_time created_at updated_at

Is there any way to solve this issue? Is it possible to do the same logic with SQL instead?

Answer 1

A direct answer to this question is not possible. I found 2 ways to resolve my issue.

First solution

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Mysql has DATEDIFF and DATE_SUB to get timestamp difference and subtract certain intervals from a timestamp. In my case, the function runs every minute. To use them, I have to refactor my database to store the time and unit in seconds in the database. Then do the calculation. I chose not to use this way because both operations are a bit heavy on the server-side since I am running the function every minute.

Second Solution

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This is the solution that I personally did in my case. Here I did the calculations while storing it in the database. Meaning? Let me explain. I created a new table notification_settings which is linked to the reminder (one-one relation). The table looks like this

id , unit , time , notify_at , repeating , created_at , updated_at

The unit and time columns are only used while displaying the reminder. What I did is, I calculated when to be notified in the notify_at column. So in the event scheduler, I need to check for the reminders at present (since I am running it every minute). The repeating column is there to keep track of whether the reminder is repeating or not. If it is repeating I re-calculate the notify_at column at the time of scheduling. Once the user is notified notify_at is set to null.