Parsing out date_entered field to capture TIME 'hh:mm:ss' based on time range
It sounds like you want

WHERE date_entered BETWEEN sysdate - interval '2' hour
                       AND sysdate


Assuming date_entered never contains future dates

WHERE date_entered &gt;= sysdate - interval '2' hour


Depending on exactly what you need (and why you're running the query), you may want to truncate the date to the hour or minute so that you're always comparing against data from the top of the hour

WHERE date_entered &gt;= trunc(sysdate - interval '2' hour, 'HH24')


Depending on why you are doing this, however, keep in mind that you may miss data if you're running every 2 hours.  If I insert a row at, say 3:59:59 pm, your job starts runs at 4:00:00 pm (looking for data between 2 and 4) and at 6 pm (looking for data between 4 and 6), and I commit at 4:00:01 pm, then neither execution of the job will return this row.