以下の例を参照してください
SELECT mydate calendar_date
,EXTRACT(WEEK FROM mydate) week_num
,EXTRACT(month FROM mydate) month_num
,to_char(mydate,'Mon') month_name
,EXTRACT(Quarter FROM mydate) quarter_num
,EXTRACT(year FROM mydate) calendar_year
,EXTRACT(DOW FROM mydate) iso_dayofweek
,to_char(mydate, 'day') dayofweek_name
FROM (
SELECT now()::DATE mydate
) t
結果：
calendar_date week_num month_num month_name quarter_num calendar_year iso_dayofweek dayofweek_name
------------- -------- --------- ---------- ----------- ------------- ------------- --------------
2015/04/24 17 4 Apr 2 2015 5 friday
generate_series()を使用できます たとえば、1年のすべての日付を取得するには：2015
select generate_series(0,364) + date'1/1/2015'
これにより、1/1/2015 - 31/12/2015 、この selectを使用します SELECT now()::DATEの代わりに 与えられた例では
2015年のテーブルを作成する場合 次に、次のクエリを使用できます
CREATE TABLE mycal_2015 AS
SELECT row_number() OVER () date_key
,mydate calendar_date
,EXTRACT(WEEK FROM mydate) week_num
,EXTRACT(month FROM mydate) month_num
,to_char(mydate,'Mon') month_name
,EXTRACT(Quarter FROM mydate) quarter_num
,EXTRACT(year FROM mydate) calendar_year
,EXTRACT(DOW FROM mydate) iso_dayofweek
,to_char(mydate, 'day') dayofweek_name
FROM (
SELECT generate_series(0, 364) + DATE '1/1/2015' mydate
) t
テーブルはselect * from mycal_2015のようになります
date_key calendar_date week_num month_num month_name quarter_num calendar_year iso_dayofweek dayofweek_name
-------- ------------- -------- --------- ---------- ----------- ------------- ------------- --------------
1 2015/01/01 1 1 Jan 1 2015 4 thursday
2 2015/01/02 1 1 Jan 1 2015 5 friday
3 2015/01/03 1 1 Jan 1 2015 6 saturday
4 2015/01/04 1 1 Jan 1 2015 0 sunday
5 2015/01/05 2 1 Jan 1 2015 1 monday
6 2015/01/06 2 1 Jan 1 2015 2 tuesday
...
.
.
.
364 2015/12/30 53 12 Dec 4 2015 3 wednesday
365 2015/12/31 53 12 Dec 4 2015 4 thursday
POSTGRSQL：EXTRACT FUNCTION
PostgreSQL抽出関数は日付からパーツを抽出します
構文：extract( unit from date )
dateは、日付部分が抽出される日付、タイムスタンプ、時刻、または間隔の値です。
unitは、日、月、分、時間などの間隔の単位タイプです
次のいずれかになります。
unit description
--------------- -----------------------------------------------------------------------------------------------------------------------------
century Uses the Gregorian calendar where the first century starts at '0001-01-01 00:00:00 AD'
day Day of the month (1 to 31)
decade Year divided by 10
dow Day of the week (0=Sunday, 1=Monday, 2=Tuesday, ... 6=Saturday)
doy Day of the year (1=first day of year, 365/366=last day of the year, depending if it is a leap year)
epoch Number of seconds since '1970-01-01 00:00:00 UTC', if date value. Number of seconds in an interval, if interval value
hour Hour (0 to 23)
isodow Day of the week (1=Monday, 2=Tuesday, 3=Wednesday, ... 7=Sunday)
isoyear ISO 8601 year value (where the year begins on the Monday of the week that contains January 4th)
microseconds Seconds (and fractional seconds) multiplied by 1,000,000
millennium Millennium value
milliseconds Seconds (and fractional seconds) multiplied by 1,000
minute Minute (0 to 59)
month Number for the month (1 to 12), if date value. Number of months (0 to 11), if interval value
quarter Quarter (1 to 4)
second Seconds (and fractional seconds)
timezone Time zone offset from UTC, expressed in seconds
timezone_hour Hour portion of the time zone offset from UTC
timezone_minute Minute portion of the time zone offset from UTC
week Number of the week of the year based on ISO 8601 (where the year begins on the Monday of the week that contains January 4th)
year Year as 4-digits
注：抽出機能はPostgreSQLバージョン8.4以降に適用されます
日付/時刻関数と演算子
generate_series（）