extract week number from date postgres
I would like to extract the week number as:
from a date formatted as:
How can I perform this in postgres?
my weeks are calculated from monday to sunday.
To get the year and the week in a single character value, use
select to_char(current_date, 'IYYY-IW');
IW returns the year and the week number as defined in the ISO standard and
IYYY returns the corresponding year (which might be the previous year).
If you need the year and the week number as numbers, use
select extract('isoyear' from current_date) as year, extract('week' from current_date) as week;
extract week number from date postgres, In 7.1.x, try: SELECT EXTRACT (WEEK FROM CURRENT_DATE);. in older postgres maybe this: SELECT EXTRACT (WEEK FROM DATE 'today');. Chris. How to get the week number from a date. To get the ISO week number (1-53) from a date in the column datecol, use SELECT EXTRACT(WEEK FROM datecol) FROM …. To get the corresponding four-digit year, use SELECT EXTRACT(ISOYEAR FROM datecol) FROM …. Read more about EXTRACT() in the PostgreSQL manual. To get the week number in a TO_CHAR pattern, use IW for the week number and IYYY for the corresponding year.
I have done like this
extract(week from cast(current_date as date)) extract(year from cast(current_date as date))
Re: Week number, Note that extract 's day of the week numbering is different from that of the to_char For date and timestamp values, the number of seconds since 1970-01-01� Get the Week Number from a Date in PostgreSQL. Ian on August 10, 2020. August 10, 2020. In PostgreSQL you can use the extract () function to get the week number from a date. You can also use the date_part () function to do the same thing.
You can do as follows
SELECT EXTRACT(year FROM current_date) FROM table ;
Documentation: 8.1: Date/Time Functions and Operators, The DATE_PART() function extracts a subfield from a date or time value. To extract the week number from a time stamp, you pass the week as the first� Use the DATE_PART () function to retrieve the week number from a date in a PostgreSQL database. This function takes two arguments. The first argument is the date part to retrieve; we use ‘week’, which returns the week number (e.g. “1” for the first week in January, the first week of the year).
PostgreSQL DATE_PART Function: Extract Year, Month, Week, etc , To extract the week number from a time stamp, you pass the week as the first argument: SELECT date_part ( 'week', TIMESTAMP '2017-09-30' ); date_part ----------- 39 (1 row) To get the current millennium, you use the DATE_PART () function with the NOW () function as follows:
The number of centuries: DAY: The day of the month (1-31) The number of days: DECADE: The decade that is the year divided by 10: Sames as TIMESTAMP: DOW: The day of week Sunday (0) to Saturday (6) N/A: DOY: The day of year that ranges from 1 to 366: N/A: EPOCH: The number of seconds since 1970-01-01 00:00:00 UTC: The total number of seconds in
WITH sub(field) AS ( SELECT CAST('20110101' AS date) -- just to test ) SELECT CASE WHEN EXTRACT (WEEK FROM field ) > 1 AND EXTRACT (MONTH FROM field) = 1 AND EXTRACT (DAY FROM field) < 3 THEN 1 ELSE EXTRACT (WEEK FROM field) END FROM sub; share. Share a link to this answer. Copy link.
- This is wrong, sometimes the first week of one calendar year starts in the previous year. Example of a bug and a solution is:
select to_char(date '2018-12-31', 'YYYY-IW'), to_char(date '2019-01-01', 'YYYY-IW'), to_char(date '2018-12-31' + (7 - extract(dow from date '2018-12-31'))::int, 'YYYY-IW'), to_char(date '2019-01-01' + (7 - extract(dow from date '2019-01-01'))::int, 'YYYY-IW')
- @Feenaboccles: a, right. When using
IWone also needs to use the isoyear
IYYY- I'll fix that
- Wow, well done on amending a 3-year old answer :) I wasn't expecting a response, just wanted to leave something for the next person to see this page 👍
- The expression
cast(current_date as date)can be simplified to
- The questions asks for both the year and the week.