select 在 sql db2 中从日期到日期之间的每一天 1 行

Question

我们的积分系统有一个古老的遗产 table，如下所示：

from date	until date	points monday	points tuesday	points wednesday	points thursday	points friday
6-12-2021	10-12-2021	10	30	20	15	5
13-12-2021	13-12-2021	10	0	0	0	0

现在对于 power bi 和我们的分析，我们想要创建一个 select 查询来生成如下结果：

date	points
6-12-2021	10
7-12-2021	30
8-12-2021	20
9-12-2021	15
10-12-2021	5
13-12-2021	10

在 db2 中如何完成这样的事情？

在此先感谢您的帮助！

Answer 1

您可以使用递归 CTE 列出所有日期，然后DECODE the result of DAYOFWEEK_ISO设置分数

with table1 (fromdate, untildate, monday, tuesday, wednesday, thursday, friday) as (
  values
  (date '2021-12-06', date '2021-12-10', 10, 30, 20, 15, 5),
  (date '2021-12-13', date '2021-12-13', 10, 0, 0, 0, 0)
  ),
alldates (fromdate, untildate, monday, tuesday, wednesday, thursday, friday, points_date) as (
  select table1.*, fromdate as points_date from table1
  union all
  select fromdate, untildate, monday, tuesday, wednesday, thursday, friday, points_date + 1 day from alldates where points_date < untildate
)
select
  points_date, decode(dayofweek_iso(points_date), 1, monday, 2, tuesday, 3, wednesday, 4, thursday, 5, friday) points
from alldates
order by points_date

select 在 sql db2 中从日期到日期之间的每一天 1 行

select 1 row for each day between from to until date in sql db2

sql

db2

date