sslaws mentioned this issue on May 2, 2022. Table 9-20 lists them. I would like to change the date into month. The date/time functions provide a powerful set of tools for manipulating various date/time types. date, count (se. 1. The following illustrates the syntax of the date_trunc function: date_trunc ('datepart', field)The PostgreSQL date_trunc() function truncates a specified timestamp or interval value to the specified part and returns the result. (Values of type date and time are cast automatically to timestamp or interval, respectively. 9. DATE_TRUNC. 0. We are also looking at upgrading to a newer version of Postgres but that is further out. Improve this answer. 0) $$ LANGUAGE SQL; Generally rounding up to. Thanks, -Lars On Thu, 20 Jul 2000, Tom Lane wrote: > Lars. PostgreSQL is a powerful database and includes various functions for managing timestamps and date times. Example:The issue could either be rounding back to GMT during the ::DATE cast (within the query), could be similar casting due to the ` - interval '1 day'` part, or could potentially be caused during the 'printing' phase (e. The basic syntax of the DATE_TRUNC function is as shown below:. If you want to cast your created_at field, you have to write like this as following: CAST (transactions. 9. Hyperloglog is a Postgres extension for doing high-compression storage and query approximations. PostgreSQL provides a number of functions that return values related to the current date and time. So using date_trunc('week',now())-'1 s'::interval; on the right side of your date operator should work. Select Current Quarter From Quarter Dates table. I'm trying to create what should be a super simple line chart showing the avg annual. But the week starts on Monday in Postgres by default. The following example shows how to use the date_trunc() function to truncate a timestamp value to hour part, as follows:first day of year + current week * 7 days = closest preceding date with same day of week as the first day of the year. The query worked fine in principle so I'm trying to integrate it in Java. 0. If, however, the number of different days is significantly lower, the problem is that PostgreSQL has no way to estimate the distribution of date_trunc 's results unless you create an index: CREATE INDEX ON test (date_trunc ('day', updated_at)); If updated_at is a timestamp without time zone, that will work fine. Example: PostgreSQL DATE_TRUNC() function : Example: Code: SELECT date_trunc('hour', timestamp '2002. PostgreSQL dynamic date_trunc function rounding up exactly to given timestamp. I want something in between like 100 milliseconds (1/10 second). Summary: in this tutorial, we will introduce you to the PostgreSQL DATE_PART() function that allows you to retrieve subfields e. 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. There are other possibilities, but 'day', 'month', and 'year. This can be combined with INTERVAL computations and the extract operation to do pretty much anything you need to with dates and times. The snippet provided below shows how to use the DATE_TRUNC () function in Postgres: DATE_TRUNC (dateField, timestamp); Specify the date field, such as year, month, day, etc. 8. Syntax: date_trunc(text, timestamp) Return Type: timestamp. I think you need to use a case statement: select (case when @timeinterval = 'day' then date (u. , hour, week, or month and returns the. Q&A for work. 1. date_trunc () The return type of the date_trunc function is a timestamp. , week, year, day, etc. date_trunc. date_trunc('hour', timestamp '2001-02-16 20:38:40') → 2001-02-16 20:00:00. select interval_date_trunc(interval '6 hours', start_date) as running_6h, count(*) from t group by running_6h; The function can be used in other cases of running interval aggregation too. 9. This apply to 15, 30 and 45 as well. Date/Time Functions and Operators. Basically this expression gives you the last day of the current quarter (provided that you remove the last closing parenthese, which otherwise is a syntax error). How to perform date_trunc query in Postgres using SQLAlchemy. Viewed 11k times. These SQL-standard functions all return values based on. The trunc () function is used for truncating numbers, not dates. The function is called time_bucket() and has the same syntax as the date_trunc() function but takes an interval instead of a time precision as first parameter. e. Pictorial Presentation of PostgreSQL DATE_PART() function. SELECT CODE, to_char (DATE, 'YYYY-MM'), count (CODE) FROM employee where group by CODE, to_char (DATE, 'YYYY-MM') Depending on whether you want the result as text or a date, you can also write it like this: SELECT CODE, date_trunc ('month', DATE), COUNT (*) FROM employee GROUP BY CODE, date_trunc ('month', DATE); Which in your. : select date_trunc_interval('15 minutes', timestamp '2020-02-16 20:48:40'); date_trunc_interval ----- 2020-02-16 20:45:00 (1 row) With this addition, it might be possible to turn the existing. For the date_part and date_trunc functions, arguments can be `year', `month', `day', `hour', `minute', and `second', as well as the more specialized quantities `decade', `century', `millenium', `millisecond', and. date_trunc('hour', timestamp '2001-02-16 20:38:40') → 2001-02-16 20:00:00. - The value for the “field” argument must be valid. 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). SELECT '2022-09-18':: date + INTERVAL '1 year'; In the above code, We have used typecast (::) operator to convert a value of one datatype into. g. This can be broken down into 4 steps: Take the current timestamp with time zone: now () Get the according local timestamp without time zone for New York: now () AT TIME ZONE 'America/New_York'. The PostgreSQL LOCALTIME function returns the current time at which the current transaction starts. gradovenko mentioned this issue on Dec 7, 2021. You can use this for PostgreSQL. The first removes the hours and smaller units from the timestamp, but still returns a timestamp, while the latter returns the timestamp cast to a date. Improve this answer. Data granularity measures the level of detail in a data structure. 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. Slobodan Pejic Slobodan Pejic. update mytable set starts_at = date_trunc('day', due_at), ends_at = date_trunc('day', due_at) + interval '1' day - interval '1' minute You could also phrase this as:. PostgreSQL provides the extract function to get a date's year and week number according to the ISO 8601 standard, which has the first week of every year containing January 4th. A similar functionality provides the Oracle compatible function TRUNC [ATE] (datetime). We’ll use it for different. Introduction to the PostgreSQL DATE_PART function. 5. Syntax. PostgreSQL's date_trunc in mySQL. The following illustrates the. 3 Answers. If I want to group a column of timestamps, say registered_at by the day on which they occurred, I can use either date_trunc('day', registered_at) or registered_at::date. postgresql date_trunc to arbitrary precision? 1. Date/Time Functions. The syntax of the LOCALTIME function is as follows:. It is slightly dirty, though, because the minimum time interval is an implementation detail of current Postgres versions. 9 postgres sql, date_trunc without extra zeroes. How to DATE_TRUNC by 10 days. The syntax for the function is DATE_TRUNC('datepart', timestamp), seems you need to use as DATE_TRUNC('month', session_utc)(this already truncates to the first date of April 2019 i. PostgreSQL - DATE/TIME Functions and Operators. Furthermore, it reclaims disk space immediately, rather than requiring a subsequent VACUUM operation. Also, you need to study the week in snowflake. Extract year from postgres date. I want this to be just 2013-02-04. 2. "PositionReport" WHERE "PositionReport". 1+) that I've overlooked. You can use this for PostgreSQL. For example. select extract (isoyear from current_date); select extract (week from current_date); But there seems to be no inverse. MessageText: function date_trunc(unknown, timestamp with time zone, unknown) does not exist Hint: No function matches the given name and argument types. date_trunc(text, timestamp) timestamp: Truncate to specified precision; see Section 9. 1. date_trunc関数の第一引数には任意の値を文字列として指定する。. Truncate a date in Postgres (latest version) 0. The TRUNC() function accepts two arguments. The DATE_TRUNC function truncates a timestamp expression or literal based on the date part that you specify, such as hour, day, or month. Let’s add a year to any date. The seconds field, including fractional. The query is not bad, but you can simplify it. To generate a series of dates this is the optimal way: SELECT t. For formatting functions, refer to Section 9. I am trying to get only date without time in postgres from the following statement: select current_date - date_trunc ('day',interval '1 month'); But returns me that: 2023-02-07 00:00:00. 52928+05:30’, the date_part() function extracted only the hour component of the timestamp. SELECT date_trunc('week', received_at) AS query_week, COUNT(DISTINCT customer_id) AS. Chris shows you how to get started building a metrics system inside your Postgres database while saving on storage space and query time. In other words, we can use this function to map (or force) a timestamp to the nearest specified interval. ) field selects 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. I use this in a group by query to get a count for a certain amount of dates. For instance, the “BETWEEN” clause, the “DATE_TRUNC()” function, and the basic comparison operators like “=”, “!=”, “>=” etc. , work with Date objects directly and not use date_trunc. Sorted by: 3. 4. Isolating hour-of-day and day-of-week with EXTRACT function. In PostgreSQL, DATE_TRUNC () is a built-in date function that truncates/trims the unnecessary part from the date/time. g. date_trunc ( text, timestamp) → timestamp. 5. Well, there are many ways to handle this, but the efficient way is to use date_trunc, as mentioned in the privous answer. timestamp)) from rollup_days as rp; To convert the timestamp back to a bigint, use extract () 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. org> Reviewed-by: Isaac Morland <isaac. created_at as timestamp) So your final query should be something like: SELECT (date_trunc ('day', CAST (transactions. Any code developed for PL/Java and Java 8 or newer is strongly encouraged to use these types for date/time manipulations, for their much better fit to the PostgreSQL types. g. The first removes the hours and smaller units from the timestamp, but still returns a timestamp, while the latter returns the timestamp cast to a date. DATE_TRUNC ('month','2020-09-12 15:23:00+05:45') gives 2020-09-01 05:45:00+05:45. Truncate to specified precision; see Section 9. 2. Various built-in functions, operators, clauses, etc. For this purpose, specify the “MONTH” as the first argument to any of the functions mentioned above and then use the GROUP BY clause. answered Aug 18, 2015 at 10:52. 2 Answers. From the documentation: date_part (): The date_part function is modeled on the traditional Ingres equivalent to the SQL-standard function extract:1 Answer Sorted by: 1 Oracle's DATE data type (which is what sysdate returns) always contains a time part which can not be removed. , week, month, and year. 0 did not follow the conventional numbering of centuries, but just returned the year field divided by 100. 1, compiled by Visual C++ build 1800, 32-bit" The data types of two columns which I am dealing with: eventtime timestamp without time zone sourceid integer NOT NULL Time zone is "Europe/Berlin". Connect and share knowledge within a single location that is structured and easy to search. The problem is we use Sunday as the first day of the week on our reports and PostgreSQL uses Monday as the. For example, date_trunc can aggregate by one second, one hour,. - Return Type: TIMESTAMP. answered Aug 18, 2015 at 10:52. 30 shows the available functions for date/time value processing, with details appearing in the following subsections. Table 9. 9. 5. Date_trunc function timestamp truncated to a specific precision. Forgive me if I am oversimplifying your question, but wouldn't a simple cast and date_trunc do the trick? SELECT date_trunc('second','2022-06-15T08:27:00. if you want timestamp instead of timestamptz cast the date to timestamp first. It takes a date part (like a decade, year, month, etc. The following code was working on Hibernate 5. to_char and all of the formatting functions let you query time however you want. only date_trunc(text,interval) and date_trunc(text,timestamp) are immutable. the_date 2000-12-31 00:00 Is there a way to tell date_trunc to do day/month/year conversions based on the timezone it is feeded with? The expected output would be: 2001-01-1 00:00+01009. Below is the example, and the syntax of the date_trunc function is as follows. now (). Its Java equivalent is: Instant. See Postgres Date/Time Functions and Operators for more info select date_trunc('month', current_date) + interval '1 month - 1 day'; Tip 2 You can also create an interval using make_interval function, useful when you need to create it at runtime (not using literals): Use the date_trunc method to truncate off the day (or whatever else you want, e. date_trunc(field, source [, time_zone ]) source is a value expression of type timestamp, timestamp with time zone, or interval. PostgreSQL provides a number of functions that return values related to the current date and time. The seconds field, including fractional. My current work around is to map date_trunc as a function and explicitly call it but it seems odd to have to do that. g. Share. I have the blow query that I'm trying to use in a BI tool. The DATE type in PostgreSQL can store a date without an associated time value: PostgreSQL uses 4 bytes to store a date value. Table 9. LOCALTIME(precision) Arguments. date_created) )AS DAY, this is my output 2013-02-04 00:00:00+00. 1) 2. date dollars 2016-10-03 1 2016-10-05 1 2016-10-10 1 2016-10-17 2 2016-10-24 2I'm a little confused about using trunc() function in postgresql. Or simpler, use the column number: group by 1 (if the expression is the first column in the select clause). Follow answered Aug 28, 2015 at 6:57. (Values of type date and time are cast automatically, to timestamp or interval respectively. 300) must add 10 minutes and collect all the line that are within this time interval, or , all records that are between 19:18:00. SELECT * FROM stud_cmp WHERE DATE_TRUNC ('day', start_date) = '2020-01-01' :: timestamp; In the above example, after comparing the start date and with date_trunc functions, it will display the three records which contain the. SELECT * FROM Conference WHERE date_start >= date_trunc ('month', current_date - interval '1' month) and date_start <. The documentation shows following usage example: SELECT date_trunc('hour', TIMESTAMP '2001-02-16 20:38:40'); Result: 2001-02-16 20:00:00 So I thougt this should work:시간값 내림: DATE_TRUNC. Teams. 9. –0. 4. DATE_TRUNC truncates the Postgres timestamp to a specified precision. g. g. One of these functions is DATE_TRUNC. PostgreSQL Date Part Hour From Interval. The function date_trunc is conceptually similar to the trunc function for numbers. A DATE column does not have a format. The DATE_TRUNC() function is used to truncate a date, time, or timestamp to a specified interval, such as the day, week, or month, in PostgreSQL and SQL Server. beikov February 2, 2023, 2:29pm 4. user330315. Try this one: select to_char (trunc_date,'FMMonth YYYY') from ( select distinct date_trunc ('month', orderdate) as trunc_date from table order by trunc_date desc ). (Values of type date and time are cast automatically to timestamp or interval, respectively. 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。date_trunc ( text, timestamp) → timestamp. This is an excerpt from my sql query. 2. When dealing with dates, it accepts as a parameter a Template Pattern for Date/Time (see link above) then a timestamp, and returns a timestamp. 9. The PostgreSQL formatting functions provide a powerful set of tools for converting various data types (date/time, integer, floating point, numeric) to formatted strings and for converting from formatted strings to specific data types. , hour, week, or month and returns the truncated timestamp or interval with a level of precision. I would like to change the date into month. to the beginning of the month, year or hour. I need it to return april 22. What could be going wrong here. Sorted by: 2. 9. This is an example:date_trunc('week', column_name) It uses the ISO definition of a week (as does Oracle's 'IW' ) so you need to apply the same date logic you used in Oracle to get the non-standard start of the week: date_trunc('week', column_name + 1) - 12 Answers. 372486-05'::timestamp with time zone); date_trunc ----- 2016-01-01 00:00:00-06 There is no such behavior when truncating to for example day: If you want to cast your created_at field, you have to write like this as following: CAST (transactions. Pad on the right of a string with a character to a certain length. In simple terms, DATE_TRUNC () extracts a TIMESTAMP/INTERVAL and truncates it to a specific level of precision. In Postgres, DATE_TRUNC () has the following intervals. 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. GROUP BY 1. In PostgreSQL, the DATE_TRUNC function is used to truncate a date, time, or timestamp value to a specified precision. (Values of type date and time are cast automatically to timestamp or. invoice_date, 'mm') Share. 61 Avg. select date_trunc('minute', now()) Edit: This truncates to the most recent minute. Ask Question Asked 11 years, 7 months ago. An alternative pproach is to use to_char function. The function date_trunc is conceptually similar to the trunc function for numbers. The most frequently used Postgres date functions and business scenarios where they come in handy: Rounding off timestamps with DATE_TRUNC function. Specifying the time zone in date_trunc is not supported in Postgresql 11. 5. 0. Read: Postgresql date_trunc function Postgresql date add year. SELECT to_char (date_trunc ('month', date), 'YYYY') AS year, to_char (date_trunc ('month', date), 'Mon') AS month, to_char (date_trunc ('month', date), 'MM') AS month_number, sum (duration) AS monthly_sum FROM timesheet GROUP BY date_trunc ('month', date); From a. CREATE INDEX ON. , line 01 (2011/01/03 19:18:00. reg = 'PH-BVA' GROUP BY 1, "PositionReport". You're right!, I was confusing date_trunc() with date_part(). To get a rounded result, add 30 seconds to the timestamp first, for example: select date_trunc('minute', now() + interval '30 second') This returns the nearest minute. 22. The syntax of the function is as follows: DATE_TRUNC ('precision', expression); where expression is a timestamp or an interval to truncate. In PostgreSQL, the DATE_TRUNC () function trims unnecessary values from the date and time and returns a result with specific precision. Follow answered Feb 26, 2018 at 23:30. 1. The DATE_TRUNC () function in Postgres truncate a date or time value to a specific precision. milliseconds. Friday afternoon and I'm fried. Share. The PostgreSQL CURRENT_TIMESTAMP () function returns the current date and time with time zone. 8. 0. The DATE_TRUNC() function will truncate timestamp or interval data types to return a timestamp or interval at a specified precision. 9. start_date) <= DATE_TRUNC ('day', q. In fact, DATE_TRUNC is returning the beggining of the month FOR THE WORKING TIME ZONE, but I need to know, in my timezone, what is the begginning of the UTC month. 3 Answers. 26 lists them. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00. The real value returned by the CURRENT_TIMESTAMP was ‘2023-06-17 14:45:08. Syntax: DATE_PART (field, source) In the above syntax the field is an identifier that is used to set the field to extract the data from the source. What is better: select date with trunc date or between. Postgres has lots of functions for interval and overlap so you can look at data that intersects. In PostgreSQL, the DATE_TRUNC function is used to truncate a date, time, or timestamp value to a specified precision. Getting the first day is easy and can be done with date_trunc. PostgreSQL releases before 8. SELECT TRUNC(CURRENT_TIMESTAMP) Postgresql. 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 :. id month 1 01/2021 2 03/2020 3 05/2019 The query I tried, select id, date_trunc('month',date)::date as date_month from schema. date_part(text, interval) double precision: 获取子域(等效于extract)； date_part('month', interval '2 years 3 months') 3: date_trunc(text, timestamp) timestamp: 截断成指定的精度； date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00: date_trunc(text, interval) interval: 截取指定的精度， We have used the date_trunc function with the where clause to compare the date in PostgreSQL as follows. Truncate date in units other than default choices using date_trunc (Postgres 9. UPPER関数 大文字に変換する. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00:. decade. A cast to timestamp (0) or timestamptz (0) rounds to full seconds: Fractions are not stored in table columns of this type. The range of values for date values in PostgreSQL is 4713 BC to 5874897 AD. 2. I just want to point out that it is often convenient to leave the value as a date. How to use the PostgreSQL Date Function: Date_Trunc. g. 9. created_at)) day when @timeinterval = 'year' then makedate (year (u. Hot Network Questions Shuffling two lists into each other Modeling a pure dipole as a function similar to a Dirac delta function Depressing story where SETI received signals from deep space but this news was suppressed Why is an internal proof of consistency. I have a table with a date field in timestamp format (ex: 2016-11-01 00:00:00). 1: Date/Time Types. 这是 PostgreSQL date_trunc() 函数的语法： date_trunc ( field TEXT , source TIMESTAMP ) -> TIMESTAMP date_trunc ( field TEXT , source TIMESTAMPTZ , time_zone TEXT ) -> TIMESTAMPTZ date_trunc ( field TEXT , source INTERVAL ) -> INTERVAL However, date_trunc('day', created) is not equivalent to the other expressions, because it returns a timestamp value, not a date. In postgres, you could phrase this as: date_trunc ('quarter', current_date) + interval '3 months' - interval '1 day'. dateoftransfer::date)::Date from table_withdates; --returns 2005-10-01. You cannot specify a format for it. The precision is used to set the number of digits in the fractional seconds precision in the second field of the returned query. +01 +02 etc depends on your time locale's daylight saving rules. ). It can also return a number truncated to the whole number if no precision is defined. 9. 4. 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 ). postgres=# SELECT date_part('hour', timestamp '2002-09-17 19:27:45'); date_part ----- 19 (1 row) date_part(text, interval) The date_part() function is used to get subfield (equivalent to extract). orm: dql: datetime_functions: date_trunc: YOUR_BUNDLE_HEREDoctrineExtensionsDateTrunc. date) AND DATE_TRUNC ('day', c. Table 10-4. 1 Answer. Q&A for work. You may create an overloaded TRUNC function in Postgresql. For example, if I have a table that looks like this. date_trunc can be really helpful if you want to roll up time fields and count by day or month. This may be a bit sub-optimal, but it works. SQLite, Oracle,. 9. In your example, you could use: SELECT * FROM myTable WHERE date_trunc('day', dt) = 'YYYY-MM-DD'; If you are running this query regularly, it is possible to create an index using the date_trunc function as well: CURRENT_DATE: DATE: Return the current date: CURRENT_TIME: TIMESTAMPTZ: Return the current time: CURRENT_TIMESTAMP: TIMESTAMPTZ: Return the current date and time with time zone at which the current transaction starts: DATE_PART: DOUBLE PRECISION: Get a field of a timestamp or an interval e. It is important to note that the time and time zone returned by this function is from the time the transactions start. PostgreSQL. But it would return a. I think the :: operator is more common in "Postgres land". Mathematical Functions and Operators #. but it's greatly complicated by the nature of your data. date; The results:見つけたのがdate_trunc関数。 date_trunc関数 「おぉ、イイネ！（・∀・）ﾆﾔﾆﾔ」となり、早速実験。 SELECT date_trunc('day', now()); 結果を見てみると 2013-05-01 00:00:00+0. The lowest and highest values of the DATE data type are 4713 BC and 5874897 AD. PostGreSQL : date_trunc() returns timestamp with timezone when used on date. 2019-04-01) Share I need to query for a date like the one in my code, and in postgreSQL i found date_trunc to "cut off" unnecessary information from the date. CREATE OR REPLACE FUNCTION last_day(date) RETURNS date AS $$ SELECT (date_trunc('MONTH', $1) + INTERVAL. date_trunc(text, timestamp) timestamp: Truncate to specified precision; see also Section 9. With PostgreSQL there are a number of date/time functions available, see here. 文章浏览阅读9. The date_trunc() function is used to truncate to specified precision. Fiddle with your system until. 1. But then you cannot use ordinal positions as. This generates a timestamp value, that you can cast if you. Postgresql extract monthYear from a date to be compared. PostgreSQL's date_trunc in mySQL. I've looked around and I can't figure out the right syntax for accessing the month and comparing with the current month. 0. I'm trying to create an index on the month and year of a date field (in 8. , date/time types) we describe the actual behavior in subsequent sections. ). 32 shows the available functions for date/time value processing, with details appearing in the following subsections. date_trunc. 9. The date_trunc function truncates a TIMESTAMP or an INTERVAL value based on a specified date part e. In Oracle, the MET time zone is DST aware and the UTC offset is +02:00:00. But it can be a bit simpler / faster: SELECT extract (days. How can I do this? I tried this and it did not work as expected. I'm trying to create quarterly average for player scores, however the default behaviour of postgres date_trunc('quarter', source) is that it starts first quarter with YYYY-01-01. to the beginning of the month, year or hour. Friday afternoon and I'm fried. One way to do this is to "truncate" the date to the start of the month, then add 8 days: vardate := date_trunc ('month', vardate)::date + 8; date_trunc returns a timestamp that's why the cast ::date is needed. ts BETWEEN a AND b is just a shorthand for writing ts >= a and ts <= b. 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). date_trunc is only defined for timestamp with time zone and timestamp inputs. If you want just the date in the current time zone, cast to a date. Replicate Oracle's `TRUNC(DATE, 'WW')` behaviour in PostgreSQL.