On hive date functions

[Matthieu Labour]

Hi
Is it possible with Hive to truncate date to a specified precision?
For example in Postgresql date_trunc('hour',timestamp '2001-02-16
20:38:40') will return 2001-02-16 20:00:00
There is the to_date function in hive
I am trying to achieve the following
select distinct date_trunc('hour', timestamp) as hour, count(*) from table
 group by hour;
Thank you for your help
Matthieu