sqlite3 - a very handy little database as it is file based and is included with almost every platform.

Convert Unix epoch time to local date and time format

Also julianday('now') as an equivalent for Oracle's sysdate 

select host, sid, datetime(started,'unixepoch','utc'), type from dbahawk_rman_summary where julianday(started) > julianday('now')-4 order by 1,2;
hn5407|crelsasa|2018-05-26 03:02:01|INCR(L1)
hn5407|crelsasa|2018-05-27 03:01:40|INCR(L1)
hn5407|crelsasa|2018-05-28 03:00:52|INCR(L0)
hn5407|loana|2018-03-30 21:00:32|DB FULL
hn5407|loana|2018-04-06 21:00:31|DB FULL
hn5407|loana|2018-04-13 21:00:35|DB FULL