AT TIME ZONE. 8. Share. PostgreSQL uses 4 bytes to store a date value. 4. Truncation does not remove the month and day; instead it sets them to the earliest date in the specified period. 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. 1. CREATE TABLE dim_date ( dim_date_id INT NOT NULL, date_actual DATE NOT NULL, epoch BIGINT NOT NULL, day_suffix VARCHAR(4) NOT NULL, day_name VARCHAR(9) NOT NULL, day_name_tr VARCHAR(9) NOT NULL,. 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. , ‘year’, ‘quarter’, ‘month’, ‘day’, ‘hour’, ‘minute’, ‘second’, etc. 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。 AT TIME ZONE. It looks to be the same value that is returned, because the provided value is already a day/month/year type. Nov 29 '12 # 3. 2. 1. 20 July 2000, 05:00:19. RTRIM. (Values of type date and time are cast. (In our example, we used month precision. 9. DATE_TRUNC truncates the Postgres timestamp to a specified precision. Thank you so much, Mr @GordonLinoff!!Learn how to round or truncate timestamps, datetimes, dates, and times in BigQuery with this concise tutorial. Use the DATE_TRUNC() function if you want to retrieve a date or time with a specific precision from a PostgreSQL database. date_trunc(field, source [, time_zone ]) source is a value expression of type timestamp, timestamp with time zone, or interval. The date_trunc function shortens timestamps so they are easier to read. 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. (Expressions of type date are cast to timestamp and can therefore be used as well. 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。. It's bad practice but you might be forgiven if you use. SELECT date_trunc('MONTH', CURRENT_DATE) + INTERVAL '1 MONTH - 1 DAY';I want to generate a series of months. 5. date_trunc () is a system function for truncating a timestamp or interval to a specified unit. A function for truncating a time value to a specified unit. For example. 文章浏览阅读9. Summary: in this tutorial, we will introduce you to the PostgreSQL DATE_PART() function that allows you to retrieve subfields e. 30 shows the available functions for date/time value processing, with details appearing in the following subsections. (. 8. Data Type Formatting Functions #. AT TIME ZONE 9. PostgreSQL provides a number of functions that return values related to the current date and time. Thank you very much for your. Extract year from postgres date. What could be going wrong here. Based on the parts extracted, create a new datetime. Table 9-27 shows the available functions for date/time value processing, with details appearing in the following subsections. Be aware of corner case pitfalls with type timestamp (or date ) depending on the current time zone setting (as opposed to timestamptz ). I need to take a DateTime value (apparently timestamp in Postgres) and determine the last quarter hour value. Syntax: date_trunc(text, timestamp) Return Type: timestamp. You can readily convert them to the format you want, get the difference between two values, and so on. For this example, we will add a new time function called AGE — which takes in 2 dates as an argument and outputs the "AGE" or the time in years and months between the dates. For some formats, ordering of month, day, and year in date input is ambiguous and there is support for specifying the expected ordering of these fields. Table 9-27 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. source is a value expression of type timestamp or interval. 2014-05-09 16:03:51 will be returned as 2014-05-01 00:00:00. Postgres Pro provides a number of functions that return values related to the current date and time. I think the shortest and most elegant way to solve this issue is to use date_trunc('quarter',d) (which will retrieve the start of the quarter) + 3 months - 1 day, and use the expression to create a FUNCTION:. com PostgreSQL version: All Operating system: All Description: date_trunc('quarter',. Share. 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. Table 9. (2) as CONCAT_WS appears to require text, not numeric input, you may have to do something like mutate (the_year = as. Summary: this tutorial shows you how to use the PostgreSQL date_trunc() function to truncate a timestamp or interval to a specified level of precision. The DATE_TRUNC () function in PostgreSQL has two required parameters: interval is the date or time interval to which the date will be truncated. We have used group by clause with the day. The date_trunc function allows values that aren’t obvious parts of timestamps, like week and quarter. 4. ) field is an identifier or string that selects. EXTRACT, date_part EXTRACT(field FROM source) The extract function retrieves subfields such as year or hour from date/time values. in general, in group by queries, does it matter whether using - functions on the date - a day table that has extraction pre-calculated. Following is an example of how I used to use date_trunc to match queried timestamps to only the last 4 months including the current month, but only if a week has passed into this month already: WHERE date_trunc('month', QUERY_DATE) BETWEEN date_trunc('month', now()) - INTERVAL '4 MONTH' AND date_trunc('month', now() - INTERVAL '1 WEEK') SELECT EXTRACT (EPOCH FROM TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-08'); Result: 982384720 SELECT EXTRACT (EPOCH FROM INTERVAL '5 days 3 hours'); Result: 442800. Example 2: Truncate a TIMESTAMP value to the beginning of the hour. See Table 5-12 for valid values for time unit s. 082224') GROUP BY date (updated_at) ORDER BY count (updated_at) DESC -- this line changed! Now you are. Say, you can truncate it to the nearest minute, hour, day, month, etc. 9. ) field selects to which precision to truncate the input value. 11. 9. Extracting and transforming date/ time data 50 XP. Pictorial Presentation of PostgreSQL DATE_TRUNC() function. 9. date; The results:pyspark. SELECT date_trunc('quarter', date - interval '2 month') + interval '2 month' AS quarter , country , device , AVG(rank) AS avg_rank , AVG(score) AS avg_score FROM player_daily_score GROUP BY 1,2,3 ORDER BY 1 desc; If id is not the PK, your database design can profit from normalization. Neither of those expressions will make use of an index on created - you would need to create an expression based index with the expression used. 27 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. I need to find the value of the previous quarter for a particular given date. DATE_FROM_UNIX_DATE. date_trunc. Use date_trunc () to get the start of the quarter and subtract dates: WITH cte (day) AS ( VALUES (date '2021-01-02') , (date '2021-02-05') ,. In existing versions of Postgres, you can use arithmetic: select t. This query, for example, works, but as soon as I try a left join with a different table there is a problem: select date_trunc ('month',created_at)::date as date , id as id from promo_code_uses order by date DESC; sounds like created_at is a standard field in many of your tables. Extracting the quarter date part from a timestamp. date_trunc () was added in PostgreSQL 7. 1. 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. SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40'); Result: 1. 31 shows the available functions for date/time value processing, with details appearing in the following subsections. confusingly at time. Conclusion. source must be a value expression of type timestamp, time, or interval. The EXTRACT() function returns a double precision value. Introduction to the PostgreSQL date_trunc function. For formatting functions, refer to Section 9. Amazon Redshift interprets the DECADE or DECADES DATEPART based on the common calendar. 9. Working with DATE, TIMESTAMP, and INTERVAL in PostgreSQL can be confusing. g. timestamp)) from rollup_days as rp; To convert the timestamp back to a bigint, use extract ()Extracting Dates using DATE_TRUNC Function; Extracting Dates using DATE_PART Function; Combining Functions for Advanced Extraction; Conclusion; Introduction: W hen working with PostgreSQL timestamp data types, it can be challenging to extract specific pieces of information, such as dates. 9. Because I have a table that contains time without time zone. If you need to, you can have your own in the following ways as a. For the first day of the month it should be 1, and for the last - you simply add one day to the date and check whether it is the first day of the next month, this would mean that the. Sorted by: 0. g. ) field is an identifier or string that selects what field to. Sorted by: 89. 9. For a date column: SELECT * FROM tbl WHERE my_date BETWEEN date_trunc('month', now())::date - 1 AND now()::date You can subtract plain integer values from a date (but not from a timestamp) to subtract days. PostgreSQL date_part function will allow retrieving subfields from the date and time value, e. note: similar question as DATE lookup table (1990/01/01:2041/12/31). You can round off a timestamp to one of these units of time: microsecond. 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. date_trunc 9. ) field is an identifier or string that selects what field to extract. Common culprits are: > > *) CASE expressions > *) COALESCE > *) casts > *) simple tranformational expressions > *) predicate string concatenation *) time/date functions, ie WHERE date_trunc( 'quarter', some_timestamp ) = '2014-1-1' Though, in this case it's probably much better to teach the parser how to turn that into a range expression. Adding date_trunc('quarter', your_date) to your start date will guarantee you start with the beginning of a quarter. We use quarterly queries quite often. 3. SELECT * FROM Conference WHERE date_start >= date_trunc ('month', current_date - interval '1' month) and date_start <. Yes, that is how you use date_trunc. start }}'::timestamp) The result of that is a timestamp from which you can subtract the interval: date_trunc. functions. If there are really 250000 different days in your table, you probably cannot do much better than this. create table. date_created >= { {date_range_start}} and l. transaction_date) but the count (distinct) will do a sort so it will take you a lot of time. This is used in subquery cal to generate a list of all dates in your data. The range of DATE datatype is from 4713 BC to 5874897 AD. 1 Answer. Select date_trunc ('week',dateTime) Date_week, Max (Ranking) Runing_Total_ID from (select datetime, id , dense_rank () over (order by datetime) as Ranking from Table1) group by 1. Share. 9. : Postgres Professional Home > mailing lists Thread: timestamp date_trunc ('quarter',. The date_trunc function returns a TIMESTAMP or an INTERVAL value. PostgreSQL provides two very similar functions DATE_PART and EXTRACT with different syntax, but identical (DATE_PART returns a double, which can lead to some loss of precision) behavior. - It accepts two arguments, a datePart, and a field. 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 start of the quarter, e. 9. , week, month, and year. SELECT SUM(orders. SELECT date_trunc('month',"BDATE") MTH, COUNT("CUSTOMER_REQUEST_ID") DELIVERIES FROM orders GROUP BY MTHSyntax: add_months(date, integer). 1. The following table lists the behaviors of the basic arithmetic operators −. FROM ( SELECT '1970-01-01' :: DATE + SEQUENCE. The LOCALTIME function takes one optional argument:. ). CREATE INDEX ON. Use the function date_trunc() instead,. yml. Luckily, there are several. extract() complies with the SQL standard, date_part() is a Postgres specific query. These SQL-standard functions all return values based on the start. Hello hackers, * Description This patch is a proposal to allow the use of word 'semester' to extract it from date in functions like EXTRACT, DATE_PART, etc and adds the letter 'S' to format the date output in to_char. 1. Note that truncation is not the same as extraction. 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. 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. Onde a origem. It takes a date part (like a decade, year, month, etc. Table 10-4. Note that the latter. extract関数の場合は、extract (month from request_time)という書き方だったが、date_trunc関数ではmonthをシングルクォーテーションで囲む必要がある。. , year, month, day, etc. Name of the column: This is defined as the name of the column we used with the date_trunc and to_char functions. 24×7×365 Technical Support Migration to PostgreSQL High Availability Deployment Database Audit Remote DBA for PostgreSQL Products Postgres Pro Enterprise Postgres Pro Standard Cloud Solutions Postgres Extensions2) source The source is a value of type TIMESTAMP or INTERVAL. Date trunc will convert the data per day wise. For example, decade 201 spans from 2000-01-01 to. Almost as it can't take any interval with units of months or more (due to varying duration). 4713~AD. 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. 5w次，点赞19次，收藏139次。摘要:Oracle有大量的日期函数可供使用,trunc, new_time,months_between,next_day,last_day,add_months,round等函数. Postgres에서는 주어진 타임스탬프를 특정 수준의 정밀도로 자르거나 반올림할 수 있습니다. ). the Use of the DATE_TRUNC () Function in PostgreSQL. Showing an example based on the output you've outlined. I'm new to sql and currently learning on postgresql, so I'm trying a command that returns aggregate value by month. all that have at least one day in common. Example 4. 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. l_date is the column where I would pull the date from. This chapter describes most of. For. 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. It also uses this format for inserting data into a date. INTERVAL '1-2' YEAR TO MONTH. I think the shortest and most elegant way to solve this issue is to use date_trunc ('quarter',d) (which will retrieve the start of the quarter) + 3 months - 1 day,. The precision values are a subset of the field identifiers that can be used with the EXTRACT() and DATE_PART() functions. The function date_trunc is conceptually similar to the trunc function for numbers. 9. DATE_SUB. 16. See the documentation for all values. This PostgreSQL tutorial explains how to use the PostgreSQL date_part function with syntax and examples. Sintaksis. EXTRACT, date_part EXTRACT (field FROM source) The extract function retrieves subfields from date/time values, such as year or hour. The PostgreSQL LOCALTIME function returns the current time at which the current transaction starts. , 2000-12-31. Specifying the time zone in date_trunc is not supported in Postgresql 11. Delaying Execution. It can be of timestamp, timestamptz, or interval type. Here is the syntax of the PostgreSQL date_trunc() function: date_trunc (field TEXT, source TIMESTAMP). 1 Answer. Saved searches Use saved searches to filter your results more quickly date_trunc ( text, timestamp with time zone, text) → timestamp with time zone. ) Details: 'quarter' is not mentioned in the doc as valid fields for date_trunc(). 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. Current Date/Time. To get sales from the first day of the month, we can use the DATE_TRUNC function. Stack OverflowNotes. Say,. This is the simplest and fastest. 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。. ) This function takes two arguments. A general solution for any time interval can be based on the epoch value and integer division to truncate. Section 9. day::date FROM generate_series (timestamp '2004-03-07' , timestamp '2004-08-16' , interval '1 day') AS t (day); Additional date_trunc () is not needed. PostgreSQL is a powerful database and includes various functions for managing timestamps and date times. The date_trunc function truncates a TIMESTAMP or an INTERVAL value based on a specified date part e. SELECT EXTRACT(QUARTER FROM TIMESTAMP '2023-03-11 17:43:17. start_date, 'start of day') <= datetime(q. , year, month, week from a date or time value. The special difficulty of your task: you want the ceiling, not the floor (which is much more common). Postgres에서 DATE_TRUNC (). date_trunc ( field, source [, time_zone ]) source is a value expression of type timestamp, timestamp with time zone, or interval. 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 ). "updated_at" BETWEEN '2012-10-17 00:00:00. js ORM for postgreSQL), im trying to group by date range, and keep a count of how many items where in that table. These SQL-standard functions all return values based on the start time of the current transaction:We have used the date_trunc function with the where clause to compare the date in PostgreSQL as follows. date_trunc. )), so that all values in a bucket are flattened to a single value (the date at. To use the EXTRACT() function for PostgreSQL convert DateTime to date operation, we have listed some examples: In PostgreSQL format date, to extract a month from a given timestamp, SELECT EXTRACT(MONTH FROM TIMESTAMP '2022-05-12 18:36:49'); Output: extract ----- 5 (1 row)The date_trunc() function is used to truncate to specified precision. Oracle has the trunc function and PostgreSQL / Redshift have the date_trunc function that allows you to truncate a timestamp to a specific unit of measure like year, quarter, month, week, etc. 9. lead_id) as "# New Leads" from leads l where l. com PostgreSQL version: All Operating system: All Description: date_trunc('quarter',. , hour, week, or month and returns the truncated timestamp or interval with a level of precision. 基本的な使い方を見ていこう。. , hour, week, or month and returns the truncated timestamp or interval with a level of precision. The image you added to the question suggests that the function is in pg_catalog, but the extension is. How do I get the quarter end date nicely?PostgreSQL 时间/日期函数和操作符 日期/时间操作符 下表演示了基本算术操作符的行为(+,*, 等)： 操作符例子结果 + date '2001-09-28' + integer '7'date '2001-10-05' + date '2001-09-28' + interval '1 hour'timestamp &#. 8. In order to ignore seconds, you can use date_trunc () function. 19, earlier I have made the following Query. 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. g. Interprets an INT64 expression as the number of days since 1970-01-01. Table 9. SELECT date_trunc. sql. In the following example, DATE_TRUNC retrieves the beginning of the current month, adds one month to retrieve the beginning of the next month, and then subtracts 1 day to determine the last day of the current month. date_trunc. g. //每30分钟 select date_trunc('quarter',now()) + interval '15 d 15 h 15 minute 30 second'; //本季度的第15天,15小时 15分 30秒 select date_trunc('quarter',now() ) - interval '1 h'; //每个季度最后一天的晚上11点 select date_trunc('quarter',now. You. The syntax of the function is as follows: DATE_TRUNC ('precision', expression); where expression is a timestamp or an interval to truncate. 8. Because that’s the way it’s implemented in Postgres and DB2. 2: I've chosen "date_period" to be just one day (and, in some places, formatted the result for ease of display). Table 9. Here’s the current timestamp. 8) Postgres DATE_TRUNC() Function. Checkout DoctrineExtensions. 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. We have converted date column data per day. Truncates a DATE, TIME, or TIMESTAMP to the specified precision. 표현범위는 BC. I have a slow query that generates a report of account activity per week over the past year. And it works. Remove the longest string that contains specified characters from the right of the input string. The precision values are a subset of the field identifiers that can be used with the EXTRACT() and DATE_PART() functions. Current Date/Time. Postgres では、 DATE_TRUNC () には次の間隔. The start should be the first month of the current year, the stop is the current date with an interval of 1 month. pto_start_date < (date_trunc ('quarter', now () - INTERVAL '1 month') + INTERVAL. The functions in this section use a format string that is compatible with JodaTime’s DateTimeFormat pattern format. You cannot use the date_part of week when using DATE_TRUNC on an INTERVAL. LastAccessDate), quarter = DATETRUNC(QUARTER,. (Expressions of type date will be cast to timestamp and can therefore be used as well. Julian calendar date (integer days since local midnight on November 24, 4714 BC) Q: quarter: RM: Month in uppercase Roman numerals (I to XII; I is January) rm: Month in lowercase Roman numerals (i to xii; i is January) TZ: Uppercase time zone abbreviation ( to_char supported ) tz: Lowercase time zone abbreviation (only to_char. 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. RTRIM (‘abcxxzx’, ‘xyz’) ‘abc’. ). Use the date_trunc method to truncate off the day (or whatever else you want, e. QUARTER: The calendar quarter of the specified date as an integer, where the January-March quarter is 1. This is a timestamp with time zone value which refers in fact to 23:59:59 on sunday, but with 2 hours of difference with UTC time, depends on your locale and settings. 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. These. In Postgresql, to truncate or extract the week of the timestamp value, pass the week as a string to the date_trunc function. id) FROM ( select to_char (date_trunc ('day', (current_date - offs)), 'YYYY-MM-DD') AS date FROM generate_series (0, 365, 1) AS offs ) d JOIN sharer_emailshare se ON (d. DATE_PART. 6. To see the schema where orafce is installed, use dx orafce. PostgreSQL での DATE_TRUNC () 関数の使用. g. The default quarter starts with January. Postgres has lots of functions for interval and overlap so you can look at data that intersects. 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. 9. Share. 9999999 which your desired condition would not include). 9. 2-1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 10. The DATE_TRUNC () function in Postgres truncate a date or time value to a specific precision. Table 9. Use the DATE_TRUNC() function if you want to retrieve a date or time with a specific precision from a PostgreSQL database. Follow. Ordering by month & year numbers in Postgres. The following illustrates the syntax of the date_trunc function: PostgreSQL - DATE/TIME Functions and Operators. It takes a date part (like a decade, year, month, etc. Description. I can classify the year by quarter using the Postgres keyword QUARTER as illustrated in the documentation just like SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40');. ) and a. PostgreSQL date_trunc examples. SELECT date_trunc ('month', l_date) month FROM this_table GROUP BY month. The date_part function is modeled on the traditional Ingres equivalent to the SQL -function extract: Take two easy steps to create date_trunc: Break down the datetime into small parts (Year, Month, Day/Hour, Minute, Second) and extract the parts you need. Postgres uses Monday. edited Aug 18, 2015 at 10:57. It can also truncate the value to a specified. 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. 5. We are also looking at upgrading to a newer version of Postgres but that is further out. date=to_char (date_trunc ('day', se. My query: SELECT distinct (CASE WHEN {PERIOD} = 'Previous Quarter' AND pto. For formatting functions, refer to Section 9. Of course then I needed to use the technique again yesterday, so it’s time to make a more permanent record for next time. 9. order_date BETWEEN [date_start] AND [date_end] GROUP BY interval. Be aware of corner case pitfalls with type timestamp (or date ) depending on the current time zone setting (as opposed to timestamptz ). created_at + interval (1 - day (u. 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. Next. The function you need here is date_trunc: select date_trunc ('second', now ()) -- or minute, hour, day, month. Either truncate the timestamp by minutes using date_trunc, which will return a timestamp without seconds, or use to_char if it is only about formatting the output: SELECT date_trunc ('minute',VISIT_DATE) FROM t; SELECT to_char (VISIT_DATE,'yyyy-mm-dd hh24:mi') FROM t; Demo:Using the DATE_TRUNC function, you can truncate to the weeks, months, years, or other date parts for a date or time field. created_at) when @timeinterval = 'month' then u. date_trunc. 9. Table 9. When storing a date value, PostgreSQL uses the yyyy-mm-dd format e. 9. Both are b-tree indexable operations. These SQL-standard functions all return values based on the start time of the current transaction: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. Getting the first day is easy and can be done with date_trunc. 1. 9. Mathematical operators are provided for many PostgreSQL types. TRUNC () and ROUND () are mathematical functions in PostgreSQL. The DATE_TRUNC() function will truncate timestamp or interval data types to return a timestamp or interval at a specified precision. Dates are stored using the DATE datatype in the PostgreSQL database. These functions all follow a common calling convention: the first argument is the value. Date_trunc. The most frequently used Postgres date functions and business scenarios where they come in handy: Rounding off timestamps with DATE_TRUNC function. "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. The syntax is: date_trunc ('hour', columnName). , and a timestamp.