oracle 从系统里取出一个月的第几周答:select date_col,to_number(to_char(trunc(sysdate,'yyyy'),'d')) year_week_day,first_day_week,week_no,week_no - first_day_week + 1 week_no from (select date_col,to_number(to_char(trunc(sysdate,'mm') + 7 - 1 ,'ww')) first_day_week,to_number(to_char(date_col +...