创建 365 天视图

2021-12-24 00:00:00 oracle11g oracle plsql date-arithmetic

如何创建包含一年中所有天数的 View.view 应填写从 1 月 1 日到 12 月 31 日的日期.我如何在 Oracle 中执行此操作?

How to Create a View with all days in year. view should fill with dates from JAN-01 to Dec-31. How can I do this in Oracle ?

如果当前年份有 365 天，view 应该有 365 行带日期.如果当前年份有 366 天，view 应该有 366 行带日期.我希望 view 有一个 DATE 类型的列.

If current year have 365 days,view should have 365 rows with dates. if current year have 366 days,view should have 366 rows with dates. I want the view to have a single column of type DATE.

推荐答案

这个简单的视图可以做到:

This simple view will do it:

create or replace view year_days as
select trunc(sysdate, 'YYYY') + (level-1) as the_day
from dual
connect by level <= to_number(to_char(last_day(add_months(trunc(sysdate, 'YYYY'),11)), 'DDD'))
/

像这样:

SQL> select * from year_days;

THE_DAY
---------
01-JAN-11
02-JAN-11
03-JAN-11
04-JAN-11
05-JAN-11
06-JAN-11
07-JAN-11
08-JAN-11
09-JAN-11
10-JAN-11
11-JAN-11

...

20-DEC-11
21-DEC-11
22-DEC-11
23-DEC-11
24-DEC-11
25-DEC-11
26-DEC-11
27-DEC-11
28-DEC-11
29-DEC-11
30-DEC-11
31-DEC-11

365 rows selected.

SQL>

日期是通过应用几个 Oracle 日期函数生成的:

The date is generated by applying several Oracle date functions:

  • trunc(sysdate, 'yyyy') 为我们提供当年的一月一日
  • add_months(x, 11) 给我们十二月的第一天
  • last_day(x) 给我们十二月三十日
  • to_char(x, 'DDD') 为我们提供了 12 月 31 日的数字，今年是 365，明年是 366.
  • 最后一个数字提供了行生成器的上限CONNECT BY LEVEL <= X
  • trunc(sysdate, 'yyyy') gives us the first of January for the current year
  • add_months(x, 11) gives us the first of December
  • last_day(x) gives us the thirty-first of December
  • to_char(x, 'DDD') gives us the number of the thirty-first of December, 365 this year and 366 next.
  • This last figure provides the upper bound for the row generator CONNECT BY LEVEL <= X

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