What are the advantages of using timestamps for storing birthdates in PHP compared to separate year, month, and day fields?

Using timestamps for storing birthdates in PHP has several advantages compared to using separate year, month, and day fields. Timestamps allow for easier date calculations and comparisons, such as determining age or sorting by birthdate. They also take up less storage space and simplify database queries.

// Storing birthdate as a timestamp
$birthdate = strtotime('1990-05-15');

// Retrieving birthdate from timestamp
echo date('Y-m-d', $birthdate);