SQL 在 Postgresql 中获取星期几
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Get days of week in Postgresql
提问by Reena
Had been trying to figure out a select query to display days of week such as Monday, Tuesday, Wednesday, etc. I ended up with a select query displaying dates of a week,
一直试图找出一个选择查询来显示星期几，例如星期一、星期二、星期三等。我最终得到了一个显示一周日期的选择查询，
select ((date_trunc('week',current_date)::date) + (i+6)) as week_date
from generate_Series(0,6) i;
Is there a way to get the result as Monday, Tuesday and so on.
有没有办法得到周一、周二等的结果。
采纳答案by Eelke
You could do just:
你可以这样做：
VALUES ('Sunday'), ('Monday'), ('Tuesday'), ('Wednesday'), ('Thursday'), ('Friday'), ('Saturday');
回答by
Just use extract:
只需使用提取物：
extract(dow from date_column::timestamp)
from whatever_table;
This returns 0 for Sunday, 1 for Monday,...,6 for Saturday.
这将在星期日返回 0，星期一返回 1，...，星期六返回 6。
Edit:Or, since you apparently don't need anything that actually requires grabbing the day of week from a given date and you just want a single column with the fixed string values representing the names of the days of the week, just create a table...
编辑：或者，由于您显然不需要任何实际上需要从给定日期获取星期几的东西，而您只需要一个带有代表星期几名称的固定字符串值的单列，只需创建一个表...
回答by dannio
In Postgres 9 onwards there's:
在 Postgres 9 以后有：
to_char(date, 'dy');
to_char(date, 'dy');
which would return your date into the day of the week as a text value
这会将您的日期作为文本值返回到星期几
回答by Reena
The following query also works
以下查询也有效
select to_char((date_trunc('week',current_date)::date) + i,'Day') as wkday from generate_series(0,6) i
回答by Kevin Nguyen
creates a single field array that you unnest
创建一个您取消嵌套的单个字段数组
select day_of_week
from unnest(
array
['Sunday',
'Monday',
'Tuesday',
'Wednesday',
'Thursday',
'Friday',
'Saturday']
) as day_of_week
