How can you convert a time and date into a timestamp in PHP?

To convert a time and date into a timestamp in PHP, you can use the strtotime() function. This function takes a date/time string and converts it into a Unix timestamp, which is a numeric value representing the number of seconds since the Unix Epoch (January 1, 1970 00:00:00 GMT). Simply pass the date/time string as an argument to strtotime() and it will return the corresponding timestamp.

$date = "2022-12-31 23:59:59";
$timestamp = strtotime($date);
echo $timestamp;