format {string} [optional] - Use one of the following arguments to determine the format of the returned string. Note that this parameter has no impact on time zone — see note above. If an argument is not passed in, the date format is used by default.
date — formats the string as a date, based on the Date Format selected in Set Preferences.
timeofday — formats the string as a time (hour and minutes), based on the Time Format selected in Set Preferences.
datetime — formats the string as a concatenation of date and time (hour and minutes), based on the Date Format and Time Format selected in Set Preferences
datetimetz — formats the string as a concatenation of date and time (hour, minutes and seconds), based on the Date Format and Time Format selected in Set Preferences