有两个日期数据START_DATE,END_DATE,欲得到这两个日期的时间差(以天,小时,分钟,秒,毫秒):天:ROUND(TO_NUMBER(END_DATE - START_DATE))小时:ROUND(TO_NUMBER(END_DATE - START_DATE) * 24)分钟:ROUND(TO_NUMBER(END_DATE - START_DATE) * 24 * 60)秒:ROUND(TO_NUMBER(END_DATE - START_DATE) * 24 * 60 * 60