How to convert timestamp to oracle Date type

How to convert timestamp(milliseconds to 1970-1-1) to oracle Date type

 

* convert timestamp to date

 

select to_date( '1970-01-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss')+ 3600000 /86400000 as timestamp  from dual

 

timestamp

-----------------------------

1970-01-01 01:00:00.0

 

* convert  date to timestamp

 

select (to_date('2010-09-01 16:00:00','yyyy-mm-dd hh24:mi:ss') - to_date('1970-01-01','yyyy-mm-dd'))*86400000 as aDate from dual

 

aDate

-----------------------------

1283356800000

 

Note: 86400000 = 24*60*60*1000 (total milliseconds of one day)