Oracle sql按当前日期对周天数进行排序

Question

select day,
 CASE day
  WHEN  1 THEN 1
  WHEN  2 THEN 2
  WHEN  3 THEN 3
  WHEN  4 THEN 4
  WHEN  5 THEN 5
  WHEN  6 THEN 6
  WHEN  7 THEN 7
  else 0
  END as day_nr
from week where day in (1,2,3,4,5,6,7)
order by day_nr asc

Answer 1

如果您试图按一周中的某一天对一组日期进行排序，其中星期六是第一个，那么请考虑按修改后的日期进行排序：

create table t1(my_date date);
insert into t1
select trunc(sysdate)+rownum
from dual
connect by level <= 20

select
  my_date,
  to_char(my_date,'Day'),
  to_char(my_date,'D')
from
  t1
order by
  to_char(my_date + 1,'D');

http://sqlfiddle.com/#！4/5940b/3

缺点是它不是很直观，所以如果使用此方法，请添加代码注释。

case day
  when 1 then 3
  when 2 then 4
  when 3 then 5
  when 4 then 6
  when 5 then 7
  when 6 then 1 -- saturday
  when 7 then 2
end

case
  when day <= 5 then day + 2
  else               day - 5
end

order by case