统计两个日期之间的工作日的数量

统计两个日期之间的工作日的数量
比如输入 from 01/05/2016 to 25/06/2016
得出结果
40

实现

select sum(decode(by_day,'saturday',0,'sunday',0,1)) as work_day_count from (
SELECT trim(to_char(
    to_date('01/05/2016','DD/MM/YYYY')--from
    +rownum-1,'day')) as by_day FROM dual connect by rownum<=(
    to_date('25/06/2016','DD/MM/YYYY')--to
    -
    to_date('01/05/2016','DD/MM/YYYY')--from
    ));