with t as
(select to_timestamp('2015-01-01 11:13:15.023456',
'yyyy-mm-dd hh24:mi:ss.ff9') t1,
to_timestamp('2015-01-01 12:13:15.123556',
'yyyy-mm-dd hh24:mi:ss.ff9') t2
from dual)
select
abs((trunc(t1 -
0,
'mi')
-
trunc((t2 -
0),
'mi'))
*
24
*
60
*
60
+
extract(second
from t1 - t2))
from t

输出结果: 3600.1001