1、select to_char(trunc(mm_lastdate-mm_createdate),'hh24') from metinform_mantain;
2、select to_char(trunc(sysdate-mm_createdate),'hh24') from metinform_mantain;
2、select to_char(trunc(sysdate-mm_createdate),'hh24') from metinform_mantain;
2.select (sysdate-mm_createdate)*24 from metinform_mantain;