time interval format srting

Hello,

I've been searching the docs on a simple way to convert a time
_duration_ in seconds to the format dd:hh:mm:ss, but I can't find it.

90061 --> 1d 1h 1m 1s

(90061=24*3600+3600+60+1)

any ideas ?

I've been using to_char and to_timestamp to format dates/timestamps...
but this is diferent... I want to format time intervals, durations..

cheers
Joao