compare and convert format for two different date

this script compare two date and merge year, month, day based.
eg: start_date: 2011-11-15 00:00, end_date: 2011-12-5 00:00
result: 15 November - 5 December 2011

Usage

print convertDateRange('2011-11-15 00:00','2011-12-05 00:00');