Anytime you have a question about a particular function in PHP, the easiest way to get quick answers is by visiting php.net, which has great documentation on all of the language's capabilities.
Looking up a function is easy, just visit http://php.net/<function name> and it will forward you to the appropriate place. For the date function, we'll visit http://php.net/date.
We immediately learn a couple things about this function by examining its signature:
string date ( string $format [, int $timestamp = time() ] )
First, it returns a string. That's what the first string in the above code means. Secondly, the first parameter is expected to be a string containing the format. There is an optional second parameter for passing in your own timestamp (to construct strings from some time other than now).
date("d-m-Y") // produces something like 03-12-2012
In this code, d represents the day of the month (with a leading 0 is necessary). m represents the month, again with a leading zero if necessary. And Y represents the full 4-digit year. All of these are documented in the aforementioned link.
To satisfy your request of getting the hours, minutes, and seconds, we need to give a quick look at the documentation to see which characters represents those particular units of time. When we do that, we find the following:
h 12-hour format of an hour with leading zeros 01 through 12
i Minutes with leading zeros 00 to 59
s Seconds, with leading zeros 00 through 59
With this in mind, we can no create a new format string:
date("d-m-Y h:i:s"); // produces something like 03-12-2012 03:29:13
Hope this is helpful, and I hope you find the documentation has benefiting to your development as I have to mine.
You can have both formats as an argument to the function date():
date("d-m-Y H:i:s")
Check the manual for more info : http://php.net/manual/en/function.date.php
As pointed out by @ThomasVdBerge to display minutes you need the 'i' character
You can combine both in the same date function call
date("d-m-Y H:i:s");
Source: Stackoverflow.com