DATESUBDATE(date1, date2, op):返回两个日期之间的时间差。
op表示返回的时间单位:
"s",以秒为单位。
"m",以分钟为单位。
"h",以小时为单位。
"d",以天为单位。
"w",以周为单位。
示例:
DATESUBDATE("2008-08-08", "2008-06-06","h")等于1512。
公式
DATESUBDATE(CONCATENATE(today()," 14:15:00"),CONCATENATE(today()," 08:30:00"),"m")
//转换为00:00:00

right(time(0,trunc(DATESUBDATE(CONCATENATE(today()," 14:15:00"),CONCATENATE(today()," 08:30:00"),"m")),(DATESUBDATE(CONCATENATE(today()," 14:15:00"),CONCATENATE(today()," 08:30:00"),"m")-trunc(DATESUBDATE(CONCATENATE(today()," 14:15:00"),CONCATENATE(today()," 08:30:00"),"m")))*60),8)