In PHP it is very easy to sort an array of dates and times. All you need to do is convert it to a (integer) timestamp, and then do a normal sort. Here are more details:

First, convert the dates into a timestamp

A timestamp is time measured in the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT). The current timestamp (when this page was last cached, anyway) is: 1575882558 (time()).

Because there is no standard PHP array function for sorting date strings we will have to convert it ourselves. But we can make a closure, and pass that to usort(&$array, $compare_func) (which lets us define our own function to do the comparisons for the sorting)

The custom comparison function for usort takes 2 parameters. It returns either -1, 0, or 1 depending on how they compare (1 if $a is less than $b; -1 if $a is greater than $b; 0 if equal). We can use PHP's spaceship operator for this (<=>) .

Let's set up the data:

And now the comparison function:

Now we have everything we need - let's sort that data!

array:6 [
  0 => "20 April 1998"
  1 => "5 April 1999"
  2 => "9 September 2000"
  3 => "10 September 2000"
  4 => "9 September 2020"
  5 => "10 September 2020"
]