If your client session isn't in the same timezone as the server the database is on (or says it isn't anyway, via your NLS settings), mixing the
CURRENT_* functions will return different values. They are all correct, they just represent different things. It looks like your server is (or thinks it is) in a +4:00 timezone, while your client session is in a +4:30 timezone.
You might also see small differences in the time if the clocks aren't synchronised, which doesn't seem to be an issue here.
~ Answered on 2013-07-29 13:49:33