- It accepts two arguments, a datePart, and a field. Sorted by: 3. Jun 27, 2014. ) field selects to which precision to truncate the input value. The text was updated successfully, but these errors were encountered:Partition by date range PostgreSQL scans all partitions. Postgres, Update TIMESTAMP to current date but. (Values of type date and time are cast automatically to timestamp or interval, respectively. – zhrist. Truncate to specified precision. The following table lists the behaviors of the basic arithmetic operators −. Current Date/Time. RPAD (‘ABC’, 6, ‘xo’) ‘ABCxox’. Postgresql extract monthYear from a date to be compared. 5. Postgresql date_trunc with time zone shifts zone by 1 hr. answered Aug 18, 2015 at 10:52. This function truncates a date/time value to a specified precision. 32 shows the available functions for date/time value processing, with details appearing in the following subsections. ac. 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). 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: The precision values are a subset of the field identifiers that can be used with the EXTRACT() and DATE_PART() functions. Depending on your requirements, another option is to adjust the precision of the timestamp column itself -. These SQL-standard functions all return values based on. 2. ShareTeams. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00. In PostgreSQL I am extracting hour from the timestamp using below query. 9. Say, you can truncate it to the nearest minute, hour, day, month, etc. 次のように実例を示すとわかりやすいです。. 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。. The. MySQL- Truncating Date-Time in a query. 22 Documentation. Author: John Naylor <john. Checkout DoctrineExtensions. end_date) >= DATE_TRUNC ('day', q. PostgreSQL: Documentation: 9. These SQL-standard functions all return values based on the start time of the. 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. x: CriteriaBuilder cb = entityManager. Let’s add a year to any date. 2 Answers. Modified 1 year, 7 months ago. 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. Add a comment. (In our example, we used month precision. Here’s the current timestamp. PostgreSQL provides a number of functions that return values related to the current date and time. Truncation means setting specific parts of. Let’s add a year to any date. Yes, I believe that's the case. Thanks again! 👍 1. 9. When used with a timestamp, truncates the timestamp to a date (day) value and returns a timestamp with or without time zone depending on type of the argument. This is not in any of other answers, which suggest to_char() and date_trunc(). 6. timestamp)) from rollup_days as rp; To convert the timestamp back to a bigint, use extract ()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 This query is working for me to give me the running total of total IDs by week. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00. When storing a date value, PostgreSQL uses the yyyy-mm-dd format e. Current Date/Time. (Values of type date and time are cast automatically to timestamp or interval, respectively. You may be misunderstanding what date_trunc does. 1 Answer. Pictorial Presentation of PostgreSQL DATE_TRUNC() function. g. Follow. Also per the H2 docs Trunc:. ADVERTISEMENT. 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: Introduction to the PostgreSQL DATE_PART function. 3, PostgreSQL 9. CREATE INDEX ON. You can use this for PostgreSQL. Return the current month as text in postgres. Evan Carroll. The time zone in result is shifted by 1hr: select date_trunc('year','2016-08-05 04:01:58. only date_trunc(text,interval) and date_trunc(text,timestamp) are immutable. So instead of having. How can I do this? I tried this and it did not work as expected. 3. Syntax: date_trunc ('datepart', field) The datepart argument in the above syntax is used to truncate one of the field ,below listed field type: millennium. date) AND DATE_TRUNC ('day', c. Syntax. 2. g. 15. - It accepts two arguments, a datePart, and a field. 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. 0. We are also looking at upgrading to a newer version of Postgres but that is further out. For formatting functions, refer to Section 9. For example. performance. Read: Postgresql date_trunc function Postgresql date add year. Integer division truncates. created), 'YYYY-MM-DD')) GROUP BY d. Fully managed, PostgreSQL-compatible database for enterprise workloads. Current Date/Time. 0. for example 2018-10-15 will be 2018-10-01 and 2018-10-30 also will be 2018-10-01. SELECT EXTRACT(EPOCH FROM TIMESTAMP '2011-05-17 10:40:28. 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. -- date_trunc(日付の切り捨て)の構文 date_trunc( 精度 , 日付・時刻 ); 精度には'year'、'month'、'day'等を指定します。. 0. 31 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. Example. These queries work fine in oracle but am in the process of converting it to a postgres query but it complains. Use the aggregate FILTER clause in Postgres 9. end_date) >= DATE_TRUNC ('day', q. The second is more concise, but Postgres-specific. We’ll use it for different. SELECT * FROM table WHERE DATE_TRUNC('day', date ) >= Start Date AND DATE_TRUNC('day', date ) <= End Date Now this solution took : 1. SELECT date_trunc('MONTH', CURRENT_DATE) + INTERVAL '1 MONTH - 1 DAY'; Tip 2. select date_trunc('minute', now()) Edit: This truncates to the most recent minute. 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. SELECT date_trunc ('day', time), "PositionReport". The trunc () function is used for truncating numbers, not dates. 7) PostgreSQL Now (): Display without milliseconds. date_trunc ( text, timestamp) → timestamp. Share. century. 4 or later. Isolating hour-of-day and day-of-week with EXTRACT function. In PostgreSQL, DATE_TRUNC Function is used to truncate a timestamp type or interval type with specific and high level of precision. 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. If you want both quarter and year you can use date_trunc: SELECT date_trunc ('quarter', published_date) AS quarter. EXTRACT. In Postgresql, we can also add a year to the current date using the INTERVAL data type. No errors but it doesn't perform the update. The TRUNC() function accepts two arguments. reg = 'PH-BVA' GROUP BY 1, "PositionReport". EXTRACT (MONTH FROM input) AS "Month". The PostgreSQL date_trunc() function truncates a specified timestamp or interval value to the specified part and returns the result. The following code was working on Hibernate 5. ). createQuery. "updated_at" BETWEEN '2012-10-17 00:00:00. Finally… The date_bin function is adaptable and offers many new features on top of what PostgreSQL already has to offer. The following illustrates the syntax of the date_trunc function: date_trunc ('datepart', field) Code language: SQL (Structured Query Language) (sql) date_trunc ( field, source [, time_zone ]) source is a value expression of type timestamp, timestamp with time zone, or interval. 31 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. Definition of PostgreSQL Trunc () PostgreSQL’s trunc () function is used to truncate the decimal places to a certain precision. How to use the date_trunc function for biweekly grouping. 1994-10-27. 1. "type. Ask Question Asked 10 years, 9 months ago. Gordon Linoff went further in his. PostgreSQL provides a large number of functions and operators for the built-in data types. 4 and i noticed a strange behavior when using date_trunc. Thanks, but just for your own sake, you should maybe consider making use of Hibernate APIs if you want to get the best out of your ORM. I want to create an index that returns the same output as this query; --takes 2005-10-12 select date_trunc ('month',table_withdates. A block range index entry points to a page (the atomic unit of how PostgreSQL stores data) and. The DATE_TRUNC () function is particularly useful for time series analysis to understand how a value changes over time. It will not convert the value to a date. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00. Sorted by: 1. 7. date_trunc ( text, timestamp) → timestamp. It looks like this: select date_trunc('month',now()). For instance, the “BETWEEN” clause, the “DATE_TRUNC()” function, and the basic comparison operators like “=”, “!=”, “>=” etc. ; some date parts include others: i. 662522'); date_trunc --------------------- 2022-05-16 12:00:00. I don't have an explanation for why casting your timestamp to a date doesn't work for you, but try the date_trunc() function instead. the Use of the DATE_TRUNC () Function in PostgreSQL. Mathematical operators are provided for many PostgreSQL types. (Values of type date and time are cast automatically, to timestamp or interval respectively. The date_trunc() function in PostgreSQL is used to truncate a timestamp or interval value to a specified unit. Relating to this question. 9. PostgreSQL provides a number of functions that return values related to the current date and time. 5. *, (first_week + ( (date - first_week::date) / 14)*14 * interval '1 day')::date as biweek from (select t. Extract year from postgres date. 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. Q&A for work. Learn how to round or truncate timestamps in PostgreSQL for effective time-based grouping using the date_trunc function. 0. The function date_trunc is conceptually similar to the trunc function for numbers. In this case, it is used to truncate the result of the subtraction operation to seconds. In time-series analysis, the granularity could be on intervals of years, quarters, months, weeks, days, or hours. For now, I do a workaround using time_bucket('1 day', timestamp) or include it as part of CTE / with, from which I will call the on date_trunc('month', time_bucketed_day_column). Example 1: Truncate a DATE value to the beginning of the month. The second one which use DATE_TRUNC will tranc any date to the first day of the month. Now, Let us create index BTREE index on the created_at column. 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. Finally, it returns the truncated part with a specific precision level. SELECT date_trunc( 'day', to_timestamp(requests. 5. DROP FUNCTION IF EXISTS DATE_TRUNC; CREATE FUNCTION DATE_TRUNC( in_granularity ENUM('hour', 'day', 'month', 'year'), in_datetime datetime(6) ) RETURNS datetime(6). 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. ) field selects 9. , hour, week, or month and returns the truncated. select date_trunc ('minute', created_at), -- or hour, day, week, month, year count(1) from users group by 1. Sorted by: 3. 1, PostgreSQL 9. ). 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. What is the linq equivalent to sql trunc date? 0. 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_trunc(text, timestamp) timestamp: Truncate to specified precision; see also Section 9. It will return the date truncated to month precision, e. 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;. The Oracle code that I posted returns april 22, so I need postgres to do the same. date_trunc still gives me the whole date. 876944') * 1000; would give. So current_date - 1 would be enough. Table 8-9. The following table lists all window functions provided by PostgreSQL. 2014-05-09 16:03:51 will be returned as 2014-05-01 00:00:00. Table 9. 0. I am using Datagrip for Postgresql. - It retrieves the trimmed part with a specific precision level. 9. Herouth Maoz <[email protected]. 0. These SQL-standard functions all return values based on the start. 1) 2. What is better: select date with trunc date or between. Table 9-27 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. date AT TIME ZONE 'UTC'))? I need to be rounding down to full days (and weeks, etc. And best solution is 1st that suggested by marco-mariani. , hour, week, or month and. The PostgreSQL function you need here is date_trunc. Otherwise, the result has the same day component as date. I want something in between like 100 milliseconds (1/10 second). Syntax. date_trunc(text, timestamp) timestamp: Truncate to specified precision; see Section 9. Example: PostgreSQL DATE_TRUNC() function : Example: Code: SELECT date_trunc('hour', timestamp '2002-09-17 19:27:45'); Sample. In Postgres, DATE_TRUNC () has the following intervals. *, min (date_trunc ('week', date)) over () as first_week from t ) t; Here is a db<>fiddle. The "century" field is an identifier or string that indicates the century subfield. These SQL-standard functions all return values based on. In our example, we use the column end_date (i. 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. is in the Gregorian calendar year 2015. The DATE_TRUNC() function in Postgres truncate a date or time value to a specific precision. To filter this to only the most recent completed hour, so like the original post: if the current time is 2:30,. Consequently, the timestamp will be rounded/truncated based on the specified date field. Current Date/Time. 9. date_trunc¶. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00. morland@gmail. postgresql ignore milliseconds from timestamp when doing a select statement. Postgresql date to string format. They are both the same. 9. 1 Answer. SELECT TO_CHAR(timestamp_column, 'YYYY-MM-DD HH24:MI') AS formatted_ts FROM table_name;. The DATE type in PostgreSQL can store a date without an associated time value: PostgreSQL uses 4 bytes to store a date value. SELECT date_trunc ('month', CURRENT_DATE) + interval '1 month - 1 day'; Share. ADVERTISEMENT. day. The query will return a result with a single column labeled “uptime” that represents the duration of the PostgreSQL database server’s uptime. Sorted by: 5. Practical examples would include analyzing company’s quarterly. 11. Its Java equivalent is:1. Table 9-28 shows the available functions for date/time value processing, with details appearing in the following subsections. Use date_trunc (): where generated_time >= date_trunc ('hour', current_timestamp) That actually assumes no future times in your table. If we want to look at order growth month over month, we’d use a truncation function in Postgres: #Truncate date specificity SELECT DATE_TRUNC(order_time, ‘month’), COUNT(*) as count_orders FROM orders GROUP BY 1 ORDER BY 1 DESC The DATE_TRUNC() function grabs the month and year from the date so you can get a. gradovenko mentioned this issue on Dec 7, 2021. Alternatively, create a function in postgres date_trunc_day(timestamp) that calls date_trunc('day', timestamp) and call the new function instead. postgres sql, date_trunc without extra zeroes. If you want to know how many seconds passed since Jan. 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: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. Add date_bin function Similar to date_trunc, but allows binning by an arbitrary interval rather than just full units. for example 2018-10-15 will be 2018-10-01 and 2018-10-30 also will be 2018-10-01. How to round off milliseconds value from timestamp(0) in PostgreSQL? 3. SELECT date_trunc ( 'day', to_timestamp (requests. The full docs in section 9. I think, what you want to do is: SELECT date (updated_at), count (updated_at) as total_count FROM "persons" WHERE ("persons". A função DATE_TRUNC do Postgres pode nos ajudar a “truncar” uma data, bem, mas o que isso quer dizer? É simples, ela retorna a data inicial de um intervalo. Functions and Operators. 2014-05-09 16:03:51 will be returned as 2014-05-01 00:00:00. 9. The LOCALTIME function takes one optional argument:. date_trunc ( week 部分付き) 入力週を切り捨てて月曜日に開始します。 入力週を切り捨てて、定義された週の最初の日に開始します。 last_day ( week 部分付き) 入力週の日曜日を返します。 定義された週の最初の日からの相対的な入力週の最終日を返します。The DATE_TRUNC() method. created_at as timestamp) So your final query should be something like: SELECT (date_trunc ('day', CAST (transactions. Syntax. 5 introduced a feature called block range indexes (aka BRIN ) that is incredibly helpful in efficiently searching over large time series data and has the benefit of taking up significantly less space on disk than a standard B-tree index. date_trunc('hour', timestamp '2001-02-16 20:38:40') → 2001-02-16 20:00:00. PostgreSQL expected 1095 rows – and there are in fact 1096 rows. I made psql query but i need to convert it into typeorm code as i'm new to typeorm stack. If you want just the date in the current time zone, cast to a date. But the week starts on Monday in Postgres by default. 27. start }}'::timestamp) The result of that is a timestamp from which you can subtract the interval:. 8) Postgres DATE_TRUNC() Function. If you need to, you can have your own in the following ways as a. 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: CREATE FUNCTION end_of_quarter (d date) RETURNS date AS $$ SELECT CAST (date_trunc ('quarter', d) + interval '3 months' -. 9. I just sent a note about that to the pgsql-docs mailing list so hopefully it will be fixed soon. 9. answered Apr 14, 2017 at 7:37. 9. In postgres, you could phrase this as: date_trunc ('quarter', current_date) + interval '3 months' - interval '1 day'. As such, it doesn't have any good. Truncate to specified precision; see Section 9. This function with datetime or string argument is deprecated, use DATE_TRUNC instead. The function date_trunc is conceptually similar to the trunc function for numbers. g. It’s absolutely on target. Current Date/Time. Delaying Execution 9. date_trunc. 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, date_trunc('hour', interval '2 days 3 hours 40 minutes') 2 days 03:00:00 SELECT the_date FROM date_trunc('day', timestamp with time zone '2001-01-1 00:00:00+0100') as the_date results to. SELECT date_trunc('week', date::date) AS "weekly", COUNT(DISTINCT(date)) AS "working_days" FROM "public". 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). . 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. The precision values are a. If this helps (I don't know how to translate this into node. ISFINITE. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00:. 4. date_trunc can basically only round to full hours, full days, and so forth. PostgreSQL specify that. (Values of type date and time are cast automatically, to timestamp or interval respectively. 000000' AND '2012-11-07 12:25:04. The seconds field, including fractional. You might need to add explicit type casts. , week, year, day, etc. 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. RTRIM (‘abcxxzx’, ‘xyz’) ‘abc’. You can use the Now () function in PostgreSQL to display the current date and time without any mention of milliseconds. date) going over the. This list of the. SELECT SUM(rpt_unique_clicks) FROM reports WHERE rpt_datetime >= date_trunc('day', current_timestamp); On contrary, above query runs at least 15 seconds. 1. The following table lists the behaviors of the basic arithmetic operators −. 3 . The syntax of the function is as follows: DATE_TRUNC ('precision', expression); where expression is a timestamp or an interval to truncate. Next. date; The results:SELECT date_trunc('month', now()); Result: 2022-04-01 00:00:00+10. This is not in any of other answers, which suggest to_char() and date_trunc(). 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; We have used the date_trunc function with the where clause to compare the date in PostgreSQL as follows. Input Format: Dates in yellow are the dates to aggregate sales on. 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". Sorted by: 89. Mathematical operators are provided for many PostgreSQL types. The TRUNC function has the signature:. but it's greatly complicated by the nature of your data. Don't forget to keep the timezone in mind. These SQL-standard functions all return values based on. 3 Answers. Follow. 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:trunc() will set that to 00:00:00. Very unlikely to change though. - The value for the field. So if the date in the field input was 04/26/2016 this syntax returns 4,. Date/Time Functions and Operators. These SQL-standard functions all return values based on the start. 4 shows the mathematical operators that are available for the standard numeric types. Expected output format:date_trunc can basically only round to full hours, full days, and so forth. 24')); Result: 2017-02-14 20:00:00. 1 Answer. ) and a TIMESTAMP as parameters, and then it truncates the TIMESTAMP according to the specified date part. Its Java equivalent is: Instant. What you should do: Order by year and month. Below is the query. 2. 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. with ats (old_tz) as (select now() ) select old_tz, '2015-12-31'::timestamptz + (old_tz - date_trunc('day', old_tz)) new_tz from ats; OOPS. ) field selects to which precision to truncate the input value. It's not immutable because it depends on the sessions time zone setting. Note that this will return an actual timestamp; from the wording of the question, the actual column has a string, so you will need to cast it to compare: WHERE CAST ("time" as timestamp) < date_trunc ('day', now () - interval '1 month') – IMSoP. g. I just want to point out that it is often convenient to leave the value as a date. Test case: SELECT (CAST (MAX (joindate) AS date) - CAST (MIN (joindate) AS date)) as DateDifference FROM generate_series ('2014-01-01'::timestamp, '2014-02-01'::timestamp, interval '1 hour') g. openu. PostgreSQL 8. 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 :. 4 Example1 Answer. 1) precision The precision argument specifies fractional seconds precision of the second. 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. This can be handy when we want to truncate a timestamp to a given interval, for example a 10 minute interval. What is the JPQL/JPA/Hibernate equivalent of the database function date_trunc('day', (entity. Now, let us see the Date/Time operators and Functions. E. Rank the current row within its partition without gaps. callsign. We had discussed about the Date/Time data types in the chapter Data Types. timestamp '2001-09-29 03:00' - timestamp '2001-09-27 12:00'. date_trunc('hour', timestamp '2001-02-16 20:38:40') → 2001-02-16 20:00:00:. to the beginning of the month, year or hour. What is the JPQL/JPA/Hibernate equivalent of the database function date_trunc('day', (entity. 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。. It can also return a number truncated to the whole number if no precision is defined. Syntax. Load 7 more. Apparently, the PostgreSQL planner does not evaluate functions. "GROUP BY date_trunc also? @Bravo: yes you need to repeat the expression in the group by clause.