Datediff on databse firebird
datediff (hour from current_timestamp to timestamp '12-Jun-2059 06:00')
datediff (minute from time '0:00' to current_time)
datediff (month, current_date, date '1-1-1900')
datediff (day from current_date to cast(? as date))
example :
select datediff(day from current_date to cast('2018-11-01' as date)) from rdb$database
