oracle如何根据传入的时间参数，得到这个参数所在周的周一至周五的日期和星期数

select '1' AS XQBH,to_char(trunc(to_date('2020-06-28' ,'yyyy-mm-dd'),'iw'),'yyyy-mm-dd') AS RQ,'星期一' as XQ from dualUNION ALLselect '2' AS XQBH,to_cha