2. To get week start and end date (as 0 for Monday and 4 for Friday): select cast (date_trunc ('week', current_date) as date) + 0 || '-->' || cast (date_trunc ('week', current_date) as date) + 4; 2015-08-17-->2015-08-21. DATE 'YYYY- [M]M- [D]D'. This generates a timestamp value, that you can cast if you want. They are both the same. The DATE_PART() function extracts a subfield from a date or time value. You. The following example extracts the century from a time stamp: SELECT date_part('century', TIMESTAMP '2017-01-01'); date_part -----21 (1 row) Code language: SQL (Structured Query Language) (sql) Into something like: SELECT COUNT (*) = 1 INTO v_exists FROM pg_tables WHERE schemaname = 'public' AND tablename = v_partition_name and v_date_from < date_trunc ('year', current_date); This will return 1 only in the case when partition is from previous year. source is a value expression of type timestamp or interval. Any valid year (e. AT TIME ZONE. SELECT current_date + cast (abs (extract (dow FROM current_date) - 7) + 1 AS int); works, although there might be more elegant ways of doing it. This is the query: select to_char (calldate,'Day') as Day, date_trunc (calldate) as transdate, Onnet' as destination,ceil (sum (callduration::integer/60. 9. From what I'm reading, you're looking for the first and last stored day of the week, so: WITH first_stored AS (SELECT min (stored_date) as first FROM stored WHERE stored_date > DATE_TRUNC ('WEEK', NOW ()) - INTERVAL '8 DAY'), last_stored AS (SELECT max (stored_date) as last FROM stored WHERE. Format date with to_char; Setup. I have to convert a postgres query to Sequelize query. Postgres has date_trunc which operates on timestamp or interval, and:. Delaying Execution. decade. PostgreSQL provides a number of functions that return values related to the current date and time. So if the date in the field input was 04/26/2016 this syntax returns 4,. The real value returned by the CURRENT_TIMESTAMP was ‘2023-06-17. Let’s learn how the DATE_TRUNC () function work in Postgres: SELECT DATE_TRUNC ('Year', TIMESTAMP ' 2022 - 08 - 02 11: 12: 14 '); The output shows that the DATE_TRUNC () function resets all the values of the input timestamp (other than the specified date part, i. All the functions and operators described below that take time or timestamp inputs actually come in two variants: one that takes time with time zone or timestamp with time zone, and one that takes time without time zone or timestamp without time zone. , week, year, day, etc. date_trunc('month', current_timestamp) gives you the start of "this month" so in March this would be 2021-03-1 as the comparison for the upper limit is done using < it will include everything on the last day of February (including 23:59:59. Improve this answer. In Postgresql, to truncate or extract the week of the timestamp value, pass the week as a string to the date_trunc function. , week, year, day, etc. Data Type Formatting Functions. 9. MONTH: For timestamp values, the number of the month within the year (1–12) ; for interval values the number of months, modulo 12 (0–11). This is utterly confusing and annoying. PostgreSQL provides a number of functions that return values related to the current date and time. The function date_trunc is conceptually similar to the trunc function for numbers. date_trunc. The GROUP BY clause in Postgres allows us to group the table’s data based on specific column(s), making it easy to analyze and understand relationships and patterns within your data. create table foo ( first_of_month date not null check (extract (day from first_of_month) = 1) ); insert into foo (first_of_month) values ('2015-01-01. Teams. This query ran fine previously and on an interesting note, if I change the DB to Postgres 12, 13 or 14 the query also executes as expected. , “Year” in the above example) to their initials. - It retrieves the trimmed part with a specific precision level. Basically, there are two parameters we. (Expressions of type date will be cast to timestamp and can therefore be used as well. Share. Follow. See the documentation for all values. 3. Table 9. If I use the below query, I get the result as 0. config. 33. You can readily convert them to the format you want, get the difference between two values, and so on. Alternatively you can use the date_trunc function: SELECT date_trunc ('day', my_date) Share. Its Java equivalent is:Using the connect by trick for generating numbers you can extend that to generate dates and times…. 000001 WHEN 'millisecond' THEN 0. You can fix a date or remove days from current day. For a more comprehensive guide. timestamp. SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 1 second. Increasing work_mem will speed up the sort though. 参数 field. , week, month, and year. trunc() will set that to 00:00:00 If you want a date/time value (=timestamp) where the time part is 00:00:00 then you can use current_date::timestamp or date_trunc('day', current_timestamp). 9. A bigint is not "a timestamp", so you must convert the number to a date before you can apply date_trunc () on it: Select date_trunc ('day', to_timestamp (rp. They both do very different things. Column [source] ¶ Returns timestamp truncated to the unit specified by the format. Sorted by: 3. DATE_TRUNC truncates the Postgres timestamp to a specified precision. Also, you need to study the week in snowflake. There is no function you want, but as said in postgresql wiki you can define function for youself: CREATE OR REPLACE FUNCTION round_time_10m (TIMESTAMP WITH TIME ZONE) RETURNS TIMESTAMP WITH TIME ZONE AS $$ SELECT date_trunc ('hour', $1) + INTERVAL '10 min' * ROUND (date_part ('minute', $1) / 10. Modified 10 years,. ) Example of grouping sales from orders by month: select SUM(amount) as sales, date_trunc('month', created_at) as date from orders group by. Valid units for unit are (case-insensitive): 'YEAR', 'YYYY', 'YY': truncate to the first date of the year that the expr falls in, the time part will be zero out. Nice. This query compares revenue per quarter for 2018. Date_trunc function is used to truncate in specified precision. , hour, week, or month and returns the truncated. 0. 5. 26 lists them. Postgres date_trunc quarter with a custom start month. (Values of type date and time are cast automatically to timestamp or interval, respectively. I found these two procedures that abstract equivalent logic: CREATE OR REPLACE FUNCTION first_of_week(date) returns date AS $$ SELECT ($1::date-(extract('dow' FROM $1::date)*interval '1 day'))::date; $$ LANGUAGE SQL STABLE STRICT; CREATE OR. The format of the date in which it is stored and retrieved in PostgreSQL is yyyy-mm- dd. This is the query: select to_char (calldate,'Day') as Day, date_trunc (calldate) as transdate, Onnet' as destination,ceil (sum (callduration::integer/60. "employees" AS "Employee" WHERE ("Employee". id, generate_series(well_schedules. 0) $$ LANGUAGE sql; Pad on the right of a string with a character to a certain length. For. ) field selects to which precision to truncate the input value. May I make a request that "Quarter" should be treated as a valid Interval (as a synonym for "3 months"), to be consistent with other date functions that allow it, such as date_trunc() and extract() ? #1. When storing a date value, PostgreSQL uses the yyyy-mm-dd format e. Sorted by: 3. ) This function takes two arguments. In the above query within the date_part() function, provided the two values, the unit or the component ‘hour’ and the CURRENT_TIMESTAMP function that returns the current time your system. New in version 2. Based on the parts extracted, create a new datetime. appointment_date::date + appointment_end_time::time. TRUNC(date, format) Code language: SQL (Structured Query Language) (sql) Arguments. You can truncate the current date to its quarter, then remove 1 day from that (and potentially cast back to date): -- You really only need the last column, the other two just show the different steps in the process SELECT DATE_TRUNC ('quarter', CURRENT_DATE) , DATE_TRUNC ('quarter', CURRENT_DATE) - '1 day'::INTERVAL. DATETIME_TRUNC(datetime_expression, part) Example: DATETIME_TRUNC('2019-04-01 11:55:00', HOUR) Output: 2019-04-01 11:00:00. AT TIME ZONE. 9. column. dim_time__month_start_date date NOT NULL, dim_time__week_start_date date NOT NULL, dim_time__quarter_start_date date NOT NULL, dim_time__year_start_date date NOT NULL, The redundant columns wouldn't even help performance of the query at hand. "W" = week of month (1-5) (the first week starts on the first day of the month) So if the month starts on Friday, the next Thursday will still be week 1, and the next Friday will be the first day of week 2. However, date_trunc('day', created) is not equivalent to the other expressions, because it returns a timestamp value, not a date. ) Details: 'quarter' is not mentioned in the doc as valid fields for date_trunc(). trunc (teste TIMESTAMP WITHOUT TIME ZONE). The function “CURRENT_TIMESTAMP” is used with the “SELECT” statement in the above example to get the current date with the timestamp also which is “2023-06-16 10:58:01. The function date_trunc is conceptually similar to the trunc function for numbers. The quarter of the year (1 - 4) that the date is in SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 1. Is that what you want?Use union all:. Here is how I make a standard quarterly score average with default quarter. たとえば、最も近い分、時間、日、月などに切り捨てることができます。. ). A column of data type TIMESTAMP or an expression that implicitly evaluates to a TIMESTAMP type. Try to envision time periods on a straight time line and move them around before your eyes and you will see the necessary conditions. Recently, I have been getting familiar with PostgreSQL(using 8. Group by on Postgresql Date Time. source must be a value expression of type timestamp, time, or interval. The range of values for date values in PostgreSQL is 4713 BC to 5874897 AD. --set the first day of the week in. Date Part Extracted from Input Date / Timestamp. date_trunc('hour', interval '2 days 3 hours 40 minutes') 2 days 03:00:00:. THE DATE_TRUNC function truncates a date, time, or timestamp value to the specified time unit. SPLIT_PART. EXTRACT (part FROM date) We state the type of extraction we want as part and then the source to be extracted date. 9. 963179 secs juin 2, 2022, 12:00 AM | 0 years 0 mons 0 days 0 hours 2 mi. To have one row per minute, even when there's no data, you'll want to use generate _ series. source must be a value expression of type timestamp, time, or interval. If the contraint should apply to the tservice as type "date" you might as well create the tservice column as type "date" instead. I need it to return april 22. I'm looking for a single function which I can substitute for date_part in this query so that it returns 65: select date_part('minutes', '65 minutes'::interval);. Only accepted if source is of timestamptz type. Two options: (1) wrap CONCAT (. , year = DATETRUNC(YEAR, u. 9. You can readily convert them to the format you want, get the difference between two values, and so on. The DATE_TRUNC function is useful when. 5. Adding date_trunc ('quarter', your_date) to your start date will guarantee you start with the beginning of a quarter. A function for truncating a time value to a specified unit. Finding the last date of the previous quarter from current date in PostgreSQL Ask Question Asked 477 times 0 For example: If my current date is 2022. (In our example, we used month precision. Sorted by: 2. Be aware of corner case pitfalls with type timestamp (or date ) depending on the current time zone setting (as opposed to timestamptz ). What I want instead is a function that takes three parameters, so I could do make_date(2000, 1, 2) and use integers instead of strings, and returns a date (not a string). Thank you so much, Mr @GordonLinoff!!The quarter of the year (1–4) that the date is in SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 1. Posted on July 24, 2020 by Ian In PostgreSQL, the date_trunc () function truncates a date/time value to a specified precision. answered Aug 18, 2015 at 10:52. g. CREATE OR REPLACE FUNCTION round_time (timestamp with time zone) RETURNS timestamp with time zone AS $$ SELECT date_trunc ('hour', $ 1) + interval '5 min' * round (date_part ('minute', $ 1) / 5. Takes two arguments, the date to truncate and the unit of. These SQL-standard functions all return. values date_trunc ('HOUR', TIMESTAMP ('2017-02-14 20:38:40. Use the DATE_TRUNC() function if you want to retrieve a date or time with a specific precision from a PostgreSQL database. You may try subtracting 3 months from the input date, and then check whether the resulting date fall within the first or second half of the year: SELECT CASE WHEN EXTRACT (month FROM input_date) - INTERVAL '3 MONTH' BETWEEN 1 AND 6 THEN 1 ELSE 2 END AS fiscal_half FROM yourTable; The trick. These. to_char and all of the formatting functions let you query time however you want. These SQL-standard functions all return. SELECT DATE_TRUNC('minute', some_date) FROM some_table; This was working fine but I got to know that index made on some_date column will be futile because indexes doesn't work with DATE_TRUNC(), Index created was as follows :. Description. I have this problem. , 2000-12-31. Also, you need to study the week in snowflake. If you pass a DATE value, the function will cast it to a TIMESTAMP value. Get the number of remaining days after excluding date ranges in a table. The function always returns a DATE. You can update the type of the column like this: ALTER TABLE your_table ALTER COLUMN tservice TYPE date; and then add the constraint like so:There are various DateTime functions as well as operators availabe in PostgreSQL. Add 1 if you prefer 1 - 12. 5. The first day of a week (for format element 'week') is defined by the parameter NLS_FIRST_DAY_OF_WEEK (also see ALTER SESSION and ALTER SYSTEM ). PostgreSQL DATE_PART () function is mainly used to return the part of the date and time; the date_part function in PostgreSQL will subtract the subfield from the date and time value. date; The results:By implementing the feature above, we are going to learn the following date functions in PostgreSQL: Truncate date with date_trunc; Extract date parts, such as weekday, month and year with date_part. PostgreSQL Date Functions Manipulation. 9. All the functions and operators described below that take time or timestamp inputs actually come in two variants: one that takes time with time zone or timestamp with time zone, and one that takes time without time zone or timestamp without time zone. date_trunc ( field, source [, time_zone ]) source is a value expression of type timestamp, timestamp with time zone, or interval. table` GROUP BY ddateTruncates a TIMESTAMP and returns a DATE. 日付や時刻を指定のところ（精度といいます）で切り捨てるには、 date_trunc関数 を使います。. Hey so im trying to query from a database, using Sequelize (Node. The PostgreSQL date_part function extracts parts from a date. (date_trunc('quarter', day)::date + '3 months - 1 day'::interval)::date AS quarter_ends_on, null AS is_end_of_quarter, null AS days_in_quarter,SELECT date_trunc($1, purchase_date) unit_of_time, SUM(total) FROM orders WHERE purchase_date >= $2 AND purchase_date <= $3 GROUP BY unit_of_time ORDER BY unit_time; [interval, startDate, endDate] The above query works correctly for when I pass in either 'month' or 'day' as the interval variable, but gives incorrect values. That is easy enough to add. 参数 field. A) Extracting from a TIMESTAMP examples. source is a value expression of type timestamp or interval. ). This function is most widely used for creating time series and aggregating at a granular level. This can be generalized to any type of grouping. Jun 27, 2014. The following table lists the behaviors of the basic arithmetic operators −. SELECT DATE_TRUNC('month', TIMESTAMP '2005-05-21 15:30:30'); Result: 2005-05-01 00;00:00 The basic syntax of the DATE_TRUNC function is as shown below: DATE_TRUNC(precision, source); where precision is the precision to which you want to truncate the date or time (e. 5. 9. Isolating hour-of-day and day-of-week with EXTRACT function. 1) date The date argument is a DATE value or an expression. Based on the parts extracted, create a new datetime. These queries work fine in oracle but am in the process of converting it to a postgres query but it complains. Elasticsearch SQL accepts also the plural for each time unit (e. date 、 time 、または timestamp を指定された精度に切り捨てます。. I've looked around and I can't figure out the right syntax for accessing the month and comparing with the current month. and while the condition is > '2018-10-01' then all dates in the month October will not be shown in the result. It takes the date part ‘qtr’ from the timestamp value in the “created_at” column (from the “shopify_orders” table). I am converting a postgres app to an Oracle app. Gets the number of intervals between two DATE values. Sorted by: 1. ) field selects to which precision to truncate the input value. The precision parameter is case-insensitive. 5. DATE_SUB. We are also looking at upgrading to a newer version of Postgres but that is further out. . 1. 8. This is how I made it: CREATE OR REPLACE FUNCTION public. 2) and found the date_trunc function extremely useful for easily matching time stamps between certain days/months/etc. To generate a series of dates this is the optimal way: SELECT t. , and a timestamp. 1 starts: 9. (Values of type date and time are cast automatically to timestamp or. From the documentation: date_part (): The date_part function is modeled on the traditional Ingres equivalent to the SQL-standard function extract:Into something like: SELECT COUNT (*) = 1 INTO v_exists FROM pg_tables WHERE schemaname = 'public' AND tablename = v_partition_name and v_date_from < date_trunc ('year', current_date); This will return 1 only in the case when partition is from previous year. and if I run it in Jan 2013, then it should give me 31 Dec 2012. Both solutions include the last day of the previous month and also include all of "today". note: similar question as DATE lookup table (1990/01/01:2041/12/31). SELECT id, name, date_trunc('quarter', date) AS date, AVG(rank) AS rank,. Note that to_date () returns a date so your code would remove the just added time part again. Connect and share knowledge within a single location that is structured and easy to search. A similar functionality provides the Oracle compatible function TRUNC [ATE] (datetime). How do I get the quarter end date nicely?The way to count weeks is to truncate the start and end timestamps to the first day of the week, then subtract days. Based on Fiscal Year system, duration. Any valid year (e. Then format date the way you want. (Values of type date and time are cast automatically to timestamp or interval, respectively. 指定した単位（month）以下の値が切り捨てられ、 年 月という結果. 28 shows the available functions for date/time value processing, with details appearing in the following subsections. Everything to the “right” of the datepart you selected will be “blank” or go back to the beginning (in other words, if you truncate your query at year, then the month, day and time will “reset” to 01-01 00:00). If there are really 250000 different days in your table, you probably cannot do much better than this. 1994-10-27. Args:. Current Date/Time. Oracle, of course, just. The DATE_PART () function extracts a subfield from a date or time value. It's best explained by example: date_trunc('hour',TIMESTAMP '2001-02. g. 9. For example, TRUNC (TO_DATE ('2013-08-05'), 'QUARTER') returns the first date in the third quarter of the year 2013, which is July 1, 2013. demo:db<>fiddle. The week number will be in the range of 1 to 53, depending on the specific date and the datestyle setting in PostgreSQL. . test=# CREATE STATISTICS mystats ON (date_trunc('day', t)) FROM t_timeseries ; CREATE STATISTICS test=# ANALYZE ; ANALYZE What you’ve just told the system is to create a sample for date_trunc(‘day’, t) and maintain this information just like simple column-related statistics. The following query SELECT the_date FROM date_trunc('day', timestamp with time zone '2001-01-1 00:00:00+0100') as the_date results to the_date 2000-12-31 00:00 Is there a way to tell . Here's an example: SELECT round (date_trunc ( 'day', your_date_column):: date) AS rounded_date FROM your_table; In this example, replace your_date_column with the actual name of the column that contains the date you want to round, and your_table with the name of the table where the column resides. 30 shows the available functions for date/time value processing, with details appearing in the following subsections. start }}'::timestamp) The result of that is a timestamp from which you can subtract the interval: date_trunc. It puts that value in. Current Date/Time. In the docs I could only find a way to create a date from a string, e. Here is how you can convert an epoch value back to a time stamp: SELECT TIMESTAMP WITH TIME ZONE 'epoch' + 982384720 * INTERVAL '1 second'; hour. The date_trunc function truncates a TIMESTAMP or an INTERVAL value based on a specified date part e. The function date_trunc is conceptually similar to the trunc function for numbers. Assuming you are using Postgres, you need quotes around your date constant and can convert to the right types: WHERE job_date >= DATE_TRUNC('month'::text, '2019. 'quarter' is valid for date_trunc() and extract() SELECT date_trunc ('quarter', now()); date_trunc-----2021-01-01 00:00:00+00 The DATE_PART () function extracts a subfield from a date or time value. However, with Postgres 14, the EXTRACT function now returns a numeric type instead of an 8-byte float. Postgres Pro provides a number of functions that return values related to the current date and time. Since this is a performance-critical part of the query, I'm wondering whether this is the fastest solution, or whether there's some shortcut (compatible with Postgres 8. What it does: The Redshift add_months function adds months, specified by integer to a date value. The following example shows how to use the date_trunc () function to truncate a timestamp value to hour part, as follows: SELECT date_trunc('hour', TIMESTAMP '2022-05-16 12:41:13. I have an sql query am trying to make to my postgres db. The quarter of the year (1 - 4) that the date is in SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 1. This is used in subquery cal to generate a list of all dates in your data. Interprets an INT64 expression as the number of days since 1970-01-01. For formatting functions, refer to Section 9. decade. 切り捨ては抽出とは異なります。例： タイムスタンプを四半期まで切り捨てると、入力タイムスタンプの四半期の最初の日の真夜中に対応するタイムスタンプが返されます。The PostgreSQL DATE_TRUNC function is used to truncate the date and time values to a specific precision (into a whole value), such as 'year', 'month', 'day', 'hour', 'minute', or 'second', in a string format. g. Here’s an example that returns the last day of the current month: SELECT (date_trunc ('month', now ()) + interval '1 month - 1 day'); Result: 2022-04-30 00:00:00+10. create index on test (date_trunc('month', foo::timestamp )); the problem with foo at time zone 'GMT' is that the expression foo at time zone 'GMT' is not itself immutable. Use the DATE_TRUNC() function if you want to retrieve a date or time with a specific precision from a PostgreSQL database. create table test (start date ,"end" date); insert into test values ('2019-05-05','2019-05-10') , ('2019-05-25','2019-06-10') , ('2019-07-05','2019-07-10') ; I am looking for the following output, where for every date between the start and end the person is available only. PostgreSQL date_part function will allow retrieving subfields from the date and time value, e. DATE_TRUNC() will return an interval or timestamp rather than a number. Improve this answer. The function date_trunc is conceptually similar to the trunc function for numbers. (. I'm making my first laravel project, using postgres, and I'd like to be able to access all the people with a birthday this month (my people table has a birthdate field that's a date). sql. My SQL is: SELECT date_trunc('week', '2020-06-01'::timestamp)::date ||'-'|| (date_trunc('week', '2020-06-01'::timestamp)+ '6 days'::interval)::date; However, using. A general solution for any time interval can be based on the epoch value and integer division to truncate. PostgreSQL provides a number of functions that return values related to the current date and time. YEAR. The most frequently used Postgres date functions and business scenarios where they come in handy: Rounding off timestamps with DATE_TRUNC function. e. SELECT * FROM generate_series(date_trunc('quarter', '2008-02-01 00:00'), '2009-01-01 12:00', '3 months');. AT TIME ZONE. timestamp '2001-09-29 03:00' - timestamp '2001-09-27 12:00'. For formatting date/time values for display, see Section 4. Syntax DATE_TRUNC(‘[interval]’, time_column) The time_column is the database column that contains the timestamp you'd like to round, and [interval] dictates your desired precision level. region, q1. How about truncating to the beginning of this month, jumping forward one month, then back one day? =# select (date_trunc ('month', now ()) + interval '1 month - 1 day')::date; date ------------ 2015-07-31 (1 row) Change now () to your date variable, which must be a timestamp, per the docs. 2. date_trunc always returns a timestamp, not a date. The date_trunc function contains the two input parameters, i. You would need to use to_timestamp () if you really want. fujitsu. Data warehouse support for the EXTRACT function Google BigQuery, Amazon Redshift, Snowflake, Postgres, and Databricks all support. I am just highlighting the date modification part) ## 6 days interval "date_trunc ('month', created_at) + (date_part ('day', created_at)::int - 1) / 6 * interval '6 day'" ## 10 min interval "date_trunc ('hour', created_at) + date_part ('minute', created_at)::int / 10 * interval '10 min'". In fact extract() gets re-written to date_part() - check the execution plan and you will see. You can also use add_months to subtract months by specifying a negative integer. You can also add the full timezone name as a third argument. If you want both quarter and year you can use date_trunc: SELECT date_trunc('quarter', published_date) AS quarter This gives the date rounded to the. 19, earlier I have made the following Query. You can now use date_trunc (text, timestamp) with Doctrine! Note: You can easily adapt this code for every additional Postgres/MySQL function. In PostgreSQL, DATE_TRUNC Function is used to truncate a timestamp type or interval type with specific and high level of precision. date_trunc. 4. Use the below aggregate function with date_trunc and to_char function to use group by day in PostgreSQL. The quarter of the year (1 - 4) that the date is in SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 1. select to_char (date_trunc ('month', l. Table 9. In this article I will go over the three date/time related data types, and the two most useful date/time functions…postgresql error: function date_trunc(unknown, text) does not exist LINE 1 #9783. lead_id) as "# New Leads" from leads l where l. When storing a date value, PostgreSQL uses the yyyy-mm-dd format e. Note that the 'first day of the week' is not uniform across databases. The quarter of the year (1 - 4) that the date is in. 31 shows the available functions for date/time value processing, with details appearing in the following subsections. One truncates a date to the precision specified (kind of like rounding, in a way) and the other just returns a particular part of a datetime. RPAD (‘ABC’, 6, ‘xo’) ‘ABCxox’. 9. If you're certain that column should always store only the first of a month, you should also use a CHECK constraint. 4 or later. These SQL-standard functions all return values based on the start. 9. This. EXTRACT, date_part. edited Aug 18, 2015 at 10:57. select cast (date_trunc ('month', current_date) as date) 2013-08-01. Your database returned: ERROR: set-returning functions are not allowed in CASE Hint: You might be able to move the set-returning function into a LATERAL FROM item. com PostgreSQL version: All Operating system: All Description: date_trunc('quarter',. The PostgreSQL date_part function extracts parts from a date. Go forth and write fearless (read-only) SQL!only date_trunc(text,interval) and date_trunc(text,timestamp) are immutable. SyntaxThe goal is to extract a portion out of a timestamp. g. Use the function date_trunc() instead, that will be faster overall. Share. g. I am trying to use the Date_Trunc for MONTH function in a SQL statement but somehow it is not working for me. date_trunc¶. Alternative option. The full-list is available in the Postgres docs. 使用函数截取日期的年份 要截取一个日期的年份，我们可以使用extract函数。1. Jimmy. Update. In other words we can use date_trunc for date values with a cast:. The extract function is primarily intended for computational processing.