9. The PostgreSQL LOCALTIME function returns the current time at which the current transaction starts. You can now use date_trunc (text, timestamp) with Doctrine! Note: You can easily adapt this code for every additional Postgres/MySQL function. Select Query SELECT (date_trunc('MONTH', now()) + INTERVAL '1 MONTH -. 9 postgres sql, date_trunc without extra zeroes. CREATE TABLE log ( log_id SERIAL PRIMARY KEY, message VARCHAR ( 255) NOT NULL , created_at TIME DEFAULT. To generate a series of dates this is the optimal way: SELECT t. Alternatively you can use the date_trunc function: SELECT date_trunc ('day', my_date) Share. CREATE OR REPLACE FUNCTION last_day(date) RETURNS date AS $$ SELECT (date_trunc('MONTH', $1) + INTERVAL. but it's greatly complicated by the nature of your data. SELECT date_trunc ('month', cast (my_date as timestamp)) FROM my_table. date_trunc('field', source) source is a value expression of type timestamp or interval. In order to group our orders by month, in PostgreSQL we'll use the date_trunc built-in function. PostgreSQL provides a number of functions that return values related to the current date and time. I have this problem. A more specific answer is: where generated_time >= date_trunc ('hour', current_timestamp) and generated_time < date_trunc ('hour', current_timestamp) + interval '1 hour'. 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. ) field selects to which precision to truncate the input value. 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. postgresql ignore milliseconds from timestamp when doing a select statement. I have an sql query am trying to make to my postgres db. I bI am generating a materialized view in Postgres and one of the columns will contain a timestamptz that is the beginning of the month. createQuery. You cannot use the date_part of week when using DATE_TRUNC on an INTERVAL. The most convenient method to group table data is the DATE_TRUNC() function, which allows us to truncate a timestamp to a specific level of precision, such as the month, day, hour, etc. 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. With PostgreSQL there are a number of date/time functions available, see here. end_date) >= DATE_TRUNC ('day', q. SELECT date_trunc ('month', l_date) month FROM this_table GROUP BY month. ). But I found that there's a trunc() function in pg_catalog. milliseconds. I have the blow query that I'm trying to use in a BI tool. The following code was working on Hibernate 5. You obviously got my point, because you added a remark to your answer that they should use a date column for the month. Follow answered Jun 10, 2020 at 14:04. Current Date/Time. 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. PostgreSQL Version: 9. Follow. That truncates the date according to the timezone of the (Grafana) client resp. But there is also no point in casting date literals to date as input parameter. date_trunc is only defined for timestamp with time zone and timestamp inputs. g. 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. The date_trunc() function in PostgreSQL is used to truncate a timestamp or interval value to a specified unit. SQLite, Oracle,. The difference between them is that the latter returns the same data type like timestamptz keeping your time zone intact. (Values of type date and time are cast automatically to timestamp or interval, respectively. 4 and i noticed a strange behavior when using date_trunc. TRUNC( date_value, format ) You are providing a string value instead of a date value and 'dd-mm-yy' is an invalid format (you just want to truncate to the start of the day using 'dd' as the format or the start of the month using 'mm' or the start of the year using 'yy' - but using all three together does not make. end_date) >= DATE_TRUNC ('day', q. E. GROUP BY 1. 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 ). 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; 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. for 00:00 to 07:29 minute will be round down to 00:00 and 07:30 to 15:00 will be round up to 15:00. I need it to return april 22. only date_trunc(text,interval) and date_trunc(text,timestamp) are immutable. 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. Pictorial Presentation of PostgreSQL DATE_TRUNC() function. SELECT DATE_PART ('days', DATE_TRUNC ('month', NOW ()) + '1 MONTH'::INTERVAL - '1 DAY'::INTERVAL ) Substitute NOW () with any other date. *, min (date_trunc ('week', date)) over () as first_week from t ) t; Here is a db<>fiddle. 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. I have a table with a date field in timestamp format (ex: 2016-11-01 00:00:00). e. Example of grouping sales from orders by month: select SUM(amount) as sales, date_trunc('month', created_at) as date from orders group by. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00. Hot Network Questions Detecting if a video mode is supported by INT 0x10The PostgreSQL EXTRACT() function retrieves a field such as a year, month, and day from a date/time value. The full docs in section 9. date_trunc always returns a timestamp, not a date. com> Reviewed-by: David Fetter <david@fetter. 1 Answer Sorted by: 2 They both do very different things. milliseconds. AT TIME ZONE. postgres=# SELECT to_char(CURRENT_DATE, 'YYYYMMDD')::integer; ┌──────────┐ │ to_char │ ╞══════════╡ │ 20190718 │ └──────────┘ (1 row) But I have to say, so working with this representation of date is strange and unhappy. For partition naming you could use year and week number in the year YYWW:. But then you cannot use ordinal positions as. The "epoch" of a timestamp represents the number of seconds elapsed since a certain time and date (1st Jan 1970, 00:00:00). For instance, the “BETWEEN” clause, the “DATE_TRUNC()” function, and the basic comparison operators like “=”, “!=”, “>=” etc. Table 9. postgres sql, date_trunc without extra zeroes. Well, there are many ways to handle this, but the efficient way is to use date_trunc, as mentioned in the privous answer. On 29/10/2018 16:26, Andreas Karlsson wrote: > On 10/29/2018 04:18 PM, Vik Fearing wrote: >> A use case that I see quite a lot of is needing to do reports and other >> calculations on data per day/hour/etc but in the user's time zone. select date_trunc('minute', now()) Edit: This truncates to the most recent minute. The DATE_TRUNC () function in Postgres truncate a date or time value to a specific precision. Essentially, time_bucket() is a more powerful version of the standard PostgreSQL date_trunc() function. Truncate a date in Postgres (latest version) 1. In PostgreSQL, DATE_TRUNC() is a built-in date function that truncates/trims the unnecessary part from the date/time. For formatting functions, refer to Section 9. PostgreSQL provides a number of functions that return values related to the current date and time. If you want both quarter and year you can use date_trunc: SELECT date_trunc ('quarter', published_date) AS quarter. 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. However, Postgres' date type does postgres sql, date_trunc without extra zeroes. ) field selects to which precision to. This is not in any of other answers, which suggest to_char() and date_trunc(). The basic syntax of the DATE_TRUNC function is as shown below: DATE_TRUNC(precision, source);. date_trunc () The return type of the date_trunc function is a timestamp. g. Thanks for the clarification. Share. Truncate it to the start of the day (still timestamp without time zone ): date_trunc ('day', (now () AT TIME ZONE 'America/New_York')) Get the. 5. g. So instead of having. PostgreSQL releases before 8. Q&A for work. Herouth Maoz <herouth@oumail. These queries work fine in oracle but am in the process of converting it to a postgres query but it complains. date_trunc. SELECT date_trunc('day', "extras"->>'sent') AS date , count(*) AS "value" FROM "document" GROUP BY 1. Thanks, -Lars On Thu, 20 Jul 2000, Tom Lane wrote: > Lars. 9. 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. Very unlikely to change though. Furthermore, it reclaims disk space immediately, rather than requiring a subsequent VACUUM operation. In Postgres, the EXTRACT(), DATE_TRUNC(), and DATE_PART() functions are used to extract the month from a date field and then use the GROUP BY clause to group the results by month. Use the date_trunc method to truncate off the day (or whatever else you want, e. You can use this for PostgreSQL. start }}'::timestamp) The result of that is a timestamp from which you can subtract the interval:. 9. Say, you can truncate it to the nearest minute, hour, day, month, etc. How to perform date_trunc query in Postgres using SQLAlchemy. For formatting functions, refer to Section 9. Using the smart "trick" to extract the day part from the last date of the month, as demonstrated by Quassnoi. select cast (date_trunc ('month', current_date) as date) 2013-08-01. Use the below command: SELECT date_trunc ('week', timestamp'2021-08-23 19:14:20'); Postgresql date_trunc week. This can be handy when we want to truncate a timestamp to a given interval, for example a 10 minute interval. The DATE_PART() function extracts a subfield from a date or time value. –I tried date_trunc which does not have the precision I need. We have used the date_trunc function with the where clause to compare the date in PostgreSQL as follows. The Timescale extension for PostgreSQL gives the ability to group by arbitrary time intervals. What is the fastest way to truncate timestamps to 5 minutes in Postgres? Postgres 13 or older SELECT date_trunc('hour', date1) AS hour_stump , (extract(minute FROM date1)::int / 5) AS min5_slot , count(*) FROM table1 GROUP BY 1, 2 ORDER BY 1, 2; You could GROUP BY two columns: a timestamp truncated to the hour and a 5-minute-slot. select count(*) as logged_users, EXTRACT(hour from login_time::timestamp) as Hour from loginhistory where login_time::date = '2021-04-21' group by Hour order by Hour;. 1) 2. and while the condition is > '2018-10-01' then all dates in the month October will not be shown in the result. EXTRACT. 0. To top it all off, you want to cross-tabulate. Share. ERROR: function date_trunc(unknown, text) does not exist HINT: No function matches the given name and argument types. 0. 000000 as a valid time, while a day for LocalTime or OffsetTime maxes out at the preceding nanosecond. You can use date_trunc function to round data value to the first day of the week. DATE_TRUNC() is a function used to round or truncate a timestamp to the interval you need. It will return the date truncated to month precision, e. An alternative pproach is to use to_char function. You can use this for PostgreSQL. 3 Answers. 3. So using date_trunc('week',now())-'1 s'::interval; on the right side of your date operator should work. You cannot specify a format for it. Introduction to the PostgreSQL date_trunc function. DATE_TRUNC는 타임스탬프 값을 받아서, 특정 단위 밑을 잘라버리는 함수다. Connect and share knowledge within a single location that is structured and easy to search. The syntax of the function is as follows: DATE_TRUNC ('precision', expression); where expression is a timestamp or an interval to truncate. g. g. I would like to change the date into month. Apr 20, 2017 at 8:39. if you want timestamp instead of timestamptz cast the date to timestamp first. And I have set up partition table for every month. The precision values are a subset of the field identifiers that can be used with the EXTRACT() and DATE_PART() functions. 1 Answer. 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 comparison. The time zone is variable. Four star feature compatibility Four star automation level Data Types PostgreSQL is using different function names. Author: John Naylor <john. This uses PostgreSQL’s date_trunc() function to return the results we want. I have TableA and it has a field of time_captured | timestamp without time zone | default now () It is being used to record when data was inserted into the table. SELECT date_trunc('day', loggedin) AS "Day" , count(*) AS "No. Introduction to the PostgreSQL DATE_PART function. 4 shows the mathematical operators that are available for the standard numeric types. How to DATE_TRUNC by 10 days. : 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. Sorted by: 5. The query is not bad, but you can simplify it. In this case I use the now() function to return the current date, and the 'month' argument modifies that date to the beginning of. That is still a distinguishable value. - It accepts a “datePart” and a “field” as arguments. PostgreSQL is a powerful database and includes various functions for managing timestamps and date times. You're right!, I was confusing date_trunc() with date_part(). Date_trunc is a function that returns a date part of a date or a time part of a time. first day of year + current week * 7 days = closest preceding date with same day of week as the first day of the year. DATE_TRUNC() will return an interval or timestamp rather than a number. In order to ignore seconds, you can use date_trunc () function. I want to use date_trunc function in PostgreSQL on my datetime column to aggregate data in a week. PostgreSQL Version: 9. Example: PostgreSQL DATE_TRUNC() function : Example: Code: SELECT date_trunc('hour', timestamp '2002. A primer on working with time in Postgres. 0. 2,521 20 21. created_at as timestamp) at time zone '+08:00'))::DATE AS period_start FROM transactions LIMIT 1. 0) $$. Finally, it returns the truncated part with a specific precision level. The PostgreSQL EXTRACT() function. As far as I know, if I want to trunc date, I need to use the date_trunc() function in posgresql. 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. Pictorial Presentation of PostgreSQL DATE_TRUNC() function. trunc() will set that to 00:00:00. SELECT date_trunc ('month', cast (my_date as timestamp)) FROM my_table. In other words we can use date_trunc for date values with a cast: select date_trunc ('month',current_date)::date; ┌────────────┐ │ date_trunc. date_trunc¶. Postgres has lots of functions for interval and overlap so you can look at data that intersects. created_at) when @timeinterval = 'month' then u. (In our example, we used month precision. select * from table where extract (hour from column1) in (8, 9) where cast (column1 as time) >= '8:00' and column1::time < '10:00'. How to truncate date in PostgreSQL? 4. In PostgreSQL, the DATE_TRUNC function is used to truncate a date, time, or timestamp value to a specified precision. Let's say you have a simple query that groups by week and looks back at the last 4 weeks: select date_trunc ('week', created_at), -- or hour, day, month, year count(1) from users where created_at > now () - interval '4 weeks' group by 1; If you ran this query midweek, say on a Wednesday. date_trunc() Examples. As you don't want to include rows from "this" month, you also need to add a condition for that. user330315. I just want to point out that it is often convenient to leave the value as a date. 9. Postgres truncates trailing zeros for timestamps. 9. Consequently, the timestamp will be rounded/truncated based on the specified date field. Learn more about Teams3 Answers. (Values of type date and time are cast automatically to timestamp or interval, respectively. The problem is date_trunc('week', datetime_column) function considers Monday as the week start day and some of my customers user different start day in calendar (like Saturday). date=to_char (date_trunc ('day', se. 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. com> Reviewed-by: Tom Lane. SELECT * FROM table WHERE DATE_TRUNC('day', date ) >= Start Date AND DATE_TRUNC('day', date ) <= End Date Now this solution took : 1. date) AND DATE_TRUNC ('day', c. Improve this answer. The day (of the month) field (1 - 31). Fixes dates issues with admin for AB#12983 and. g. Trunc date field in mysql like Oracle. Introduction to the PostgreSQL date_trunc function. In the attached patch for the March commitfest, I propose a new function date_trunc_interval(), which can truncate to arbitrary intervals, e. In this case, it is used to truncate the result of the subtraction operation to seconds. TRUNCATE quickly removes all rows from a set of tables. 2. In most databases, you can do this by converting to a date: select cast (time as date) as dte, sum (case when status = 1 then 1 else 0 end) as num_successful from t group by cast (time as date) order by dte; This assumes that 1 means "successful". 7. 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. The seconds field, including fractional. So fellow SQL aficionado's how to take the following WHERE clause in PostgreSQL and convert it to SQLite3 without using a compiled extension: WHERE DATE_TRUNC ('day', c. date_trunc('month', CURRENT_DATE) does not return the month, it returns a complete timestamp at the. date_trunc date_trunc 関数は概念的に数値に対する trunc 関数と類似しています。 date_trunc('field', source) source はデータ型 timestamp の評価式です(データ型 date と time は自動的にキャストされます)。field は timestamp の値をどの精度で切捨てるかを選択します。返り値の. 4. DATE_TRUNC. MySQL- Truncating Date-Time in a query. now (). 2. SELECT date_trunc ('week', day::DATE + 1)::date + 5 AS anchor, AVG (value) AS average FROM daily_metrics WHERE metric = 'daily-active-users' GROUP BY anchor ORDER BY. If you prefer to write standard SQL, stick to extract(). 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。. 2. 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. ts BETWEEN a AND b is just a shorthand for writing ts >= a and ts <= b. postgres=# select date(date_trunc('month',current_date)); -- 月初 date ----- 2022-10-01 (1 row) postgres=# select date(date_trunc('month',current_date) + ' 1 month. Here's the correct way to do it, with date_trunc: SELECT date_trunc ('month', txn_date) AS txn_month, sum (amount) as monthly_sum FROM yourtable GROUP BY txn_month. 9. 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. Current Date/Time. These functions all follow a common calling convention: the first argument is the value to be. date_created)::date, 'Month YYYY') as "Month / Year", count (distinct l. Partition by date range PostgreSQL scans all partitions. . Always use unambiguous ISO 8601 date format (YYYY-MM-DD - 2021-02-05), which is the default in Postgres and always unambiguous, or you depend on the current datestyle setting (and may be in for surprises). select date_trunc('year', current_date)Well, In postgres, it seems there's no such function equivalent to LAST_DAY() available in oracle. Trimming trailing :00 from output after date_trunc. 0. The date_trunc(text, timestamptz) variant seems a bit under-documented, so here are my findings:. code:Apache Superset PostgreSQL 'function date_trunc(unknown, bigint) does not exist. 31 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. 9. ERROR: function date_trunc(unknown, text) does not exist HINT: No function matches the given. SELECT CURRENT_TIMESTAMP::DATE If you need to use culture specific formatting in your. The real usefu. gradovenko mentioned this issue on Dec 7, 2021. datepart. 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. 9. ) field selects to which precision to. 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. date_trunc() Examples. date_trunc() in Postgres is the equivalent to trunc() for dates in Oracle - but it's not needed for date values in Postgres as a date does not contain a time part. 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. Table 9. Sorted by: 3. 9. This function truncates a date/time value to a specified precision. I've tried a few ways in my controller:SELECT date_trunc('month', now()); Result: 2022-04-01 00:00:00+10. The start should be the first month of the current year, the stop is the current date with an interval of 1 month. 9. you need to qualify the field with the table name. starttime) yields the start of the month in the time zone of the system that created or refreshed the materialized view. Improve this answer. Postgresql extract monthYear from a date to be compared. 3. AND (date_trunc( 'day', current_timestamp AT TIME ZONE 'America/Santo_Domingo' ) AT TIME ZONE 'America/Santo_Domingo') +. 5. DATE is an important data type that stores calendar dates in PostgreSQL. decade. Share. . 24. The DATE_TRUNC() function is particularly useful for time series analysis to understand how a value changes over time. timestamp '2001-09-29 03:00' - timestamp '2001-09-27 12:00'. 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. I want this to be just 2013-02-04. orm: dql: datetime_functions: date_trunc: YOUR_BUNDLE_HEREDoctrineExtensionsDateTrunc. It can also return a number truncated to the whole number if no precision is defined. 文章浏览阅读9. Jun 2 at 11:46. The problem is we use Sunday as the first day of the week on our reports and PostgreSQL uses Monday as the. 1 Answer. With the above query I get the information I want, but I have to change the date every day. You could truncate the date to the week's Monday, then subtract 1 day, e. The Oracle code that I posted returns april 22, so I need postgres to do the same. PostgreSQL での DATE_TRUNC() 関数の使用. The DATE_TRUNC() function reduces the granularity of a timestamp. In PostgreSQL, DATE_TRUNC Function is used to truncate a timestamp type or interval type with specific and high level of precision. 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. Introduction. I have searched and found. You might need to add explicit type casts. Modified 1 year, 1 month ago. Create Postgresql index with date_trunc. 9. Truncate to specified precision. The TRUNC function has the signature:. 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. g. 1: Date/Time Types. created_at as timestamp) So your final query should be something like: SELECT (date_trunc ('day', CAST (transactions. The seconds field, including fractional. hot to add one month to the required column by substracting one day from it in postgresql. – zhrist. Use date_trunc (): where generated_time >= date_trunc ('hour', current_timestamp) That actually assumes no future times in your table. 2 Answers. Example of grouping sales from orders by month: select SUM(amount) as sales, date_trunc('month', created_at) as date from orders group by date order by date DESC; In Postgresql, to truncate or extract the week of the timestamp value, pass the week as a string to the date_trunc function. Modified 1 year, 7 months ago. if you want timestamp instead of timestamptz cast the date to timestamp first. The query worked fine in principle so I'm trying to integrate it in Java. 2014-05-09 16:03:51 will be returned as 2014-05-01 00:00:00. (Values of type date and time are cast automatically to timestamp or interval, respectively. PostgreSQL: truncate hour/min/second from a timestamp. Input Format: Dates in yellow are the dates to aggregate sales on. 4. Example #1 – by using the date_trunc function. Note that the latter returns a timestamp with time zone, not a timestamp value. PostgreSQL Date Part Hour From Interval. They are both the same. It's not immutable because it depends on the sessions time zone setting. I just sent a note about that to the pgsql-docs mailing list so hopefully it will be fixed soon. SELECT TO_CHAR(timestamp_column, 'YYYY-MM-DD HH24:MI') AS formatted_ts FROM table_name;. date_trunc () truncates (leaves seconds unchanged) - which is often what you really want: Note that timestamp (0) and timestamptz (0) will round rather than truncate. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40'). 45 (1 row) Previous: TAN function Next: PostgreSQL ARRAY functions ARRAY_APPEND function Follow us on Facebook and Twitter for. It can be used with or without time zone, and it can be used with different data types such as date, time, or interval. g. 说明：DATE_TRUNC 函数根据您指定的日期部分（如小时、周或月）截断时间戳表达式或文本。DATE_TRUNC 返回指定的年的第一天、指定的月的第一天或指定的周的星期一。. 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.