I am trying to convert a date from yyyy-mm-dd to dd-mm-yyyy (but not in SQL); however I don\'t know how the date function requires a timestamp, and
Use strtotime() and date():
$originalDate = "2010-03-21";
$newDate = date("d-m-Y", strtotime($originalDate));
(See the strtotime and date documentation on the PHP site.)
Note that this was a quick solution to the original question. For more extensive conversions, you should really be using the DateTime class to parse and format :-)