You're right, it's there in PHP 2. https://web.archive.org/web/20000815061332/http://www.php.ne...
I think I'm remembering the Win32 binaries. At https://museum.php.net/win32/ the PHP3 binaries only have MySQL.
Shared hosts settling on MySQL probably made the difference.
Perhaps what you are remembering is a particular OS or installer's packaging.