How to validate date in laravel?

Question

Laravel

I need to display posts that do not have a deadline, but it may be that the post does not have a deadline and it also needs to be displayed. I myself wrote this, I have an error.

->whereHas('unpublished_at', function ($query) {
   return substr(date('Y-m-d', strtotime($query.'1 day')),0,10) < date('Y-m-d');
})

Logically, it should be like this deadline +1 < today

Answer 1

https://laravel.com/docs/7.x/queries#where-clauses

Answer 2

How can you mathematically compare strings through < ?
Your date('Ymd') output is a string, not a number. Convert time to Unix and then compare numbers.