MySQL時間相減,使用timestampdiff (Table schema is DataTime)

http://dreamtails.pixnet.net/blog/post/27976134-mysql%E6%99%82%E9%96%93%E7%9B%B8%E6%B8%9B,%E4%BD%BF%E7%94%A8timestampdiff-%28table-schema-is-datat

表格名稱為TimeTable.
分別有兩個columns，一個是downTime，一個是upTime.

而我們是以"分" minute來作輸出的單位， 也可使用"小時" hour為單位，或是"秒" second, "天" day, "月" month, "年" year.

mysql> select timestampdiff(minute,`downTime`,`upTime`) as Subtract from TimeTable;