Group By Hour in Oracle

[N26]

I am passing in the name of a file and the time of day it was accessed.
Like this to_char('" & thedate & "','YYYY-MM-DD HH24')
I am trying to count how many times the file was viewed on an hourly basis.

The time show up like this 2000-08-15 2:05:33 PM

will the group by to_char('" & thedate & "','HH24') work?

I have been trying to get this query to work since monday.

Thanks in advance.