What is the difference between a UNIX timestamp and a timestamp generated by the SQL function now(), and how does it affect PHP date formatting?

The main difference between a UNIX timestamp and a timestamp generated by the SQL function now() is the format they are stored in. UNIX timestamps are stored as the number of seconds since January 1, 1970, while timestamps generated by now() are stored in a different format. When working with these timestamps in PHP, you may need to convert them to the appropriate format for date formatting functions to work correctly.

// Example code snippet to convert a timestamp generated by now() to a UNIX timestamp for PHP date formatting
$timestamp_from_sql = "2022-01-01 12:00:00"; // Sample timestamp generated by now()
$unix_timestamp = strtotime($timestamp_from_sql); // Convert SQL timestamp to UNIX timestamp

// Use the UNIX timestamp for date formatting
$formatted_date = date("Y-m-d H:i:s", $unix_timestamp);
echo $formatted_date;