求分钟：

SELECT CEIL((TO_DATE('2016-07-19 10:10:10','YYYY-MM-DD HH24-MI-SS') - TO_DATE('2016-07-19 10:07:50','YYYY-MM-DD HH24-MI-SS')) * 24*60 ) as HOURS FROM DUAL;

执行结果如下

HOURS
3

求小时：

SELECT CEIL((TO_DATE('2016-07-19 15:10:10','YYYY-MM-DD HH24-MI-SS')) * 24 ) AS minutesFROM DUAL;

执行结果如下

minutes
6

求秒：

SELECT CEIL((TO_DATE('2016-07-19 10:10:10','YYYY-MM-DD HH24-MI-SS')) * 24*60*60 ) as SECOND FROM DUAL;

执行结果如下：

SECOND
140

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