Question

使用Oracle SQL，如何为：

创建结果集

每周的数字（1-7）
当天的名字（星期一，星期二，星期三等）

例如：

DAY   NAME
1     Monday
2     Tuesday
3     Wednesday
4     Thursday
5     Friday
6     Saturday
7     Sunday

Answer 1

Florin的回答是我是如何做到这一点的，但你需要对NLS设置有点小心。一周中的某一天受到NLS领域的影响，所以如果我运行它，好像我在美国一样有效：

alter session set nls_territory = 'AMERICA';

select to_char(sysdate, 'D') as d, to_char(sysdate, 'Day') as day from dual;

D DAY
- ------------------------------------
6 Friday

select level as dow,
    to_char(trunc(sysdate ,'D') + level, 'Day') as day
from dual
connect by level <= 7;

DOW DAY
--- ------------------------------------
  1 Monday
  2 Tuesday
  3 Wednesday
  4 Thursday
  5 Friday
  6 Saturday
  7 Sunday

但在英国运行的同一个查询是休息日：

alter session set nls_territory = 'UNITED KINGDOM';

select to_char(sysdate, 'D') as d, to_char(sysdate, 'Day') as day from dual;

D DAY
- ------------------------------------
5 Friday

select level as dow,
    to_char(trunc(sysdate ,'D') + level, 'Day') as day
from dual
connect by level <= 7;

DOW DAY
--- ------------------------------------
  1 Tuesday
  2 Wednesday
  3 Thursday
  4 Friday
  5 Saturday
  6 Sunday
  7 Monday

...我需要调整计算以纠正错误：

select level as dow,
    to_char(trunc(sysdate ,'D') + level - 1, 'Day') as day
from dual
connect by level <= 7;

DOW DAY
--- ------------------------------------
  1 Monday
  2 Tuesday
  3 Wednesday
  4 Thursday
  5 Friday
  6 Saturday
  7 Sunday

如果需要，您还可以单独指定用于日期名称的语言：

select level as dow,
    to_char(trunc(sysdate ,'day') + level - 1, 'Day',
        'NLS_DATE_LANGUAGE=FRENCH') as day
from dual
connect by level <= 7;

DOW DAY
--- --------------------------------
  1 Lundi
  2 Mardi
  3 Mercredi
  4 Jeudi
  5 Vendredi
  6 Samedi
  7 Dimanche

to_char() with nls_date_language和day of the week的文档以及the globalisation support guide中的更多文档。

Answer 2

select level as dow, 
    to_char(level+trunc(sysdate,'D'),'Day') as day
from dual
connect by level <= 7;

Answer 3

没有更改会话

 CASE 
    WHEN to_char(sysdate, 'd')-1 = 0 THEN 7 
    ELSE to_char(sysdate, 'd')-1 
 END

Answer 4

Select 1, 'Monday' from dual union all select 2, 'Tuesday' from dual ...

使用Oracle SQL，如何输出星期几和星期几？

4 个答案: