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). Sorted by: 3. Popular Course in this category. Ask Question Asked 11 years, 7 months ago. Jun 27, 2014. Syntax. 9. 9. To fix this, give it a name like evt_block_week and select that. source is a value expression of type timestamp or interval. We’ll create three methods using several Spring Data JPA features: public interface ArticleRepository extends JpaRepository <Article, Integer> { List<Article> findAllByPublicationDate(Date publicationDate) ; List<Article. Say, you can truncate it to the nearest minute, hour, day, month, etc. CREATE OR REPLACE FUNCTION last_day(date) RETURNS date AS $$ SELECT (date_trunc('MONTH', $1) + INTERVAL. 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 created a postgres sql function which perform truncate and then insert rows into table. TRUNC (number [, precision]) Code language: CSS (css) Arguments. I know I can use trunc() to round it to only minutes. Query the Entities. 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。. for example 2018-10-15 will be 2018-10-01 and 2018-10-30 also will be 2018-10-01. 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). The article will overview the TRUNCATE TABLE statement in SQL on particular examples and describe the differences between the TRUNCATE, DELETE, and DROP statements. Table 9-2. Introduction to PostgreSQL age () function. atZone (ZoneId. It’s noteworthy that in PostgreSQL, TRUNCATE is fully transactional. For. 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. For example, if I have 2011/05/26 09:00:00, I want 2011/05/26. TRUNCATE statement is faster than the DELETE statement to delete all the rows of a table. datepart. This apply to 15, 30 and 45 as well. 0. start_date) <= DATE_TRUNC ('day', q. serpid GROUP BY date_trunc ('month', s. If I use it like ths: select trunc(now(),'MM'). It has the same effect as DELETE. But I would like to shift the result to show last X. From the documentation:. You don't actually use the number of the quarter, just the timestamps. 456,2) AS "Truncate upto 2 decimal"; Sample Output: Truncate upto 2 decimal ----- 67. NOW () is the replacement of Oracle Sysdate in Postgres. DATE_TRUNC () will return an interval or timestamp rather than a number. -- 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。. Follow edited May 17, 2022 at 11:56. Exercise care with lower. 5. (Values of type date and time are cast automatically to timestamp or interval, respectively. The trunc () function is a mathematical function present in PostgreSQL. Mathematical Functions and Operators. This example uses TRUNC on a date to truncate it into a month. In Postgres, the TRUNC() function accepts a numeric value as an argument, trims the fractional part, and retrieves the resultant integer: TRUNC(val_1, val_2); Here, the first argument indicates the input number, while the second argument determines the number of digits to be trimmed. and while the condition is > '2018-10-01' then all dates in the month October will not be shown in the result. Delaying Execution. These SQL-standard functions all return values based on the start. You may create an overloaded TRUNC function in Postgresql. The following illustrates the syntax of the PostgreSQL TRUNC() function:. . 3. Thanks for the info about the info on logwriter. Example. 1 Answer. The date_trunc function truncates a TIMESTAMP or an INTERVAL value based on a specified date part e. You can truncate the current date to its quarter, then remove 1 day from that (and potentially cast back to date): -- You really only need the last column, the other two just show the different steps in the process SELECT DATE_TRUNC ('quarter', CURRENT_DATE) , DATE_TRUNC ('quarter', CURRENT_DATE) - '1. 300 and 19:28:00. I want to have it trucated according to the displayed timezone. date_trunc. But how can I update all rows with the truncated datetime? I have this to read the two columns and trunc the ‘datumtijd’ column to whole minutes. toLocalDateTime () When you use date_trunc ('day', now () at time zone 'Asia/Tehran') (column tehran_local_start_of_today) it indicates the start of today in Tehran local. date_trunc('month', CURRENT_DATE) does not return the month, it returns a complete timestamp at the. Finally, it returns the truncated part with a specific precision level. Here’s how you can do it: SELECT TO_CHAR (your_date_column, 'YYYY-MM-DD') AS date_string FROM your_table; your_date_column is the name of the date column you want to convert to a string. The DATE_TRUNC function truncates a timestamp expression or literal based on the date part that you specify, such as hour, day, or month. 1 I am using PostgreSQL 9. AT TIME ZONE. 9. 2 do mention both forms though. date_trunc. 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' -. SELECT id, date , date_trunc('quarter', date - interval '2 month') + interval '2 month' AS quarter FROM player_daily_score;How DELETE and TRUNCATE work. SELECT EXTRACT(EPOCH FROM TIMESTAMP '2011-05-17 10:40:28. rank, COUNT (r. BabaZuri. This list of the. So both dates have already been created and inserted into the tables, here is an example of the dates: timestamp without time zone = 2012-09-19 18:13:26. first day of year + current week * 7 days = closest preceding date with same day of week as the first day of the year. 0. SELECT MONTH (date_contact) FROM YourTable; Which will return the month number, and if you want to return the month name, then you can use DATENAME () function. Does date_trunc automatically work on current year when used with CURRENT_DATE? Yes, date_trunc('month', CURRENT_DATE) will truncate the current date. 9. 0) $$ LANGUAGE SQL; 这是 PostgreSQL date_trunc() 函数的语法： date_trunc ( field TEXT , source TIMESTAMP ) -> TIMESTAMP date_trunc ( field TEXT , source TIMESTAMPTZ , time_zone TEXT ) -> TIMESTAMPTZ date_trunc ( field TEXT , source INTERVAL ) -> INTERVAL I am wondering if it's possible to truncate dates other than using the default choices using date_trunc. GROUP BY 1. For example, month truncates to the first day of the month. This is most useful on large tables. postgres sql, date_trunc without extra zeroes. How to convert this string into timestamp in postgresql? Hot Network QuestionsThe PostgreSQL TRUNCATE TABLE command is used to delete complete data from an existing table. The trunc () function is used for truncating numbers, not dates. SELECT '2022-09-18':: date + INTERVAL '1 year'; In the above code, We have used typecast (::) operator to convert a value of one datatype into. Select date_trunc ('week',dateTime) Date_week, Max (Ranking) Runing_Total_ID from (select datetime, id , dense_rank () over (order by datetime) as Ranking from Table1) group by 1. Assuming data type timestamp. Table 8-9. SELECT * FROM stud_cmp WHERE DATE_TRUNC('day', start_date) = '2020-01. 0) $$. Friday afternoon and I'm fried. 9. , week, month, and year. These SQL-standard functions all return values based on the start. date) AND DATE_TRUNC ('day', c. However, for a large table, it is more efficient to use the TRUNCATE TABLE statement. The function date_trunc is conceptually similar to the trunc function for numbers. This may be a bit sub-optimal, but it works. The lowest and highest values of the DATE data type are 4713 BC and 5874897 AD. PostgreSQL provides a number of functions that return values related to the current date and time. The basic syntax of the DATE_TRUNC function is as shown below: DATE_TRUNC(precision, source);. 94. I think you are looking for the date_trunc () function, which is used to truncate timestamps. The date_trunc function in redshift is specifically used to truncate the specified precision. the date, from the provided timestamp. We have used the date_trunc function with the where clause to compare the date in PostgreSQL as follows. For example: SELECT user_id FROM user_logs WHERE login_date >= '2014-02-01' AND login_date < '2014-03-01'. Here are the function prototypes: FROM_UNIXTIME () – convert a unix time date into a normal date. SELECT date_trunc('MONTH', CURRENT_DATE) + INTERVAL '1 MONTH - 1 DAY';. Covers all your examples. date_trunc(text, timestamp) timestamp: Truncate to specified precision; see Section 9. The output snippet shows that the DATE_PART() function pulls out the year from the given date. jdbc. Trimming trailing :00 from output after date_trunc. execute("TRUNCATE " + tableName); System. These SQL-standard functions all return values based on the start time of. Date | T_time January 1, 2022, 12:00 AM | 0 years 0 mons -51 days -24 hours -21 mins -21. date_trunc('month', '{{ date. , ages of people, years of services of employees, etc. Use the below command: SELECT date_trunc ('week', timestamp'2021-08-23 19:14:20'); Postgresql date_trunc week. Postgres 11 or newer. In order to group our orders by month, in PostgreSQL we'll use the date_trunc built-in function. Use the aggregate FILTER clause in Postgres 9. 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). Finding events relative to the present time with NOW () and CURRENT_DATE functions. Syntax. You need a similar time function in PostgreSQL. For types without standard mathematical conventions (e. Well, there are many ways to handle this, but the efficient way is to use date_trunc, as mentioned in the privous answer. 3. date) AND DATE_TRUNC ('day', c. Users can also define their own functions and operators, as described in Part V. 9. 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. Truncate all the data in the table and just let the data of the last 6 months. If you had a date and you wanted to truncate it to the hour, you could use: date_trunc ('hour', date) If you wanted to truncate to the day, you could use this: PostgreSQL group by day is used to retrieve the data by using day basis, we have applied group by clause on date_trunc function to retrieve table data as per day basis in PostgreSQL. ) field selects to which precision to truncate the input value. date_trunc is only defined for timestamp with time zone and timestamp inputs. This chapter describes most of them, although additional special-purpose functions appear in relevant sections of the manual. –However, you can set the time portion of a timestamp, dropping the date portion entirely with date_trunc. Here’s the current timestamp. RPAD (‘ABC’, 6, ‘xo’) ‘ABCxox’. 9. Note that the upper limit was cast to a date and then I subtracted. The syntax of the LOCALTIME function is as follows:. 10. 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: In Postgresql, to truncate or extract the week of the timestamp value, pass the week as a string to the date_trunc function. You can extract the day part of the date and check its value. Follow. SELECT date_trunc('MONTH', dtCol)::date; But getting the last day is not so straight forward. There is nothing wrong with using date_trunc under the right circumstances. Return the relative rank of the current row. I want to create an index that returns the same output as this query; --takes 2005-10-12 select date_trunc ('month',table_withdates. 7. date dollars 2016-10-03 1 2016-10-05 1 2016-10-10 1 2016-10-17 2 2016-10-24 2The date_trunc(text, timestamptz) variant seems a bit under-documented, so here are my findings:. I have a table partitioned per month (timestamp column). 1. end_date) >= DATE_TRUNC ('day', q. PostgreSQL: Documentation: 9. We are using date_trunc, group by, and aggregate functions to retrieve. The corresponding function in PostgreSQL here is date_trunc. 9. - It accepts a “datePart” and a “field” as arguments. ). In other words, we can use this function to map (or force) a timestamp to the nearest specified interval. postgresql ignore milliseconds from timestamp when doing a select statement. Getting results between two dates in PostgreSQL. Note that the latter returns a timestamp with time zone, not a timestamp value. The exceptions are the MONTHS_BETWEEN function, which returns a number, and the ROUND and TRUNC functions, which do not accept timestamp or interval values at all. So current_date - 1 would be enough. PostgreSQL interval data type value involves 16 bytes storage size, which helps to store a period. 1. So instead of having. 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) - 1By implementing the feature above, we are going to learn the following date functions in PostgreSQL: Truncate date with date_trunc; Extract date parts, such as weekday, month and year with date_part. For formatting functions, refer to Section 9. 9. SELECT CONVERT (VARCHAR (3), date_contact, 100) FROM. To store date values, you use the PostgreSQL DATE data type. xml configuration file: 1. Functions and Operators. 610Z') | date_trunc | | :----- | | 2022-06-14 13:04:00 |. DATE is an important data type that stores calendar dates in PostgreSQL. 98 . So, weeks always range in [0, 52]. date_trunc “truncates” a TIMESTAMP or an INTERVAL value based on a specified date part (e. guide Postgres has date_trunc which operates on timestamp or interval, and: Values of type date and time are cast automatically to timestamp or interval, respectively. e. This is an excerpt from my sql query. We’ll use it for different. This example uses TRUNC on a date to truncate it to a day. Mathematical operators are provided for many PostgreSQL types. I have an sql query am trying to make to my postgres db. Sometimes you’ll need to specify what format the string is in through the function arguments. 例1：now()=2023-04-18 00:00:00. 0. Improve this answer. This uses PostgreSQL’s date_trunc() function to return the results we want. I. Isolating hour-of-day and day-of-week with EXTRACT function. The input timestamp is truncated to the precision of the input datepart. SELECT my_date::date::timestamp. The trunc () function is a mathematical function present in PostgreSQL. Second, you need to set the hibernate. 0. Table 9. But there is also no point in casting date literals to date as input parameter. 次のように実例を示すとわかりやすいです。. Truncation means setting specific parts of the date or time to zero or a default value while keeping the more significant parts unchanged. hot to add one month to the required column by substracting one day from it in postgresql. Example 1: date_trunc('day' , '1967-12-03 23:00:00') Result: 1967-12-03 00:00:00. The format string 'YYYY-MM-DD' specifies the desired format for the. But I found that there's a trunc() function in pg_catalog. If you want to get the start of the current month, use date_trunc, eg: SELECT date_trunc('2013-01-12'); will return 2013-01-01. It also uses this format for inserting data into a. AND (date_trunc( 'day', current_timestamp AT TIME ZONE 'America/Santo_Domingo' ) AT TIME ZONE 'America/Santo_Domingo') +. We typically have to calculate ages in business applications e. Date_trunc function timestamp truncated to a specific precision. 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. The date part to which to truncate the timestamp value. 9. Its Java equivalent is:Truncate date by month with custom start day in postgres. 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. source is a value expression of type timestamp or interval. Date_trunc function is used to truncate in specified precision. 1: Date/Time Types. SELECT the_date FROM date_trunc('day', timestamp with time zone '2001-01-1 00:00:00+0100') as the_date results to. Postgres has date_trunc which operates on timestamp or interval, and: Values of type date and time are cast automatically to timestamp or interval, respectively. How to use the date_trunc function for biweekly grouping. For example, the value 00200203 represents a duration of 20 years, 2 months, and 3 days. edited Aug 18, 2015 at 10:57. answered Aug 18, 2015 at 10:52. Note there can be ambiguity in the months returned by age because different months have a different number of days. 9. Get subfield. 10. SELECT date_trunc('week', date::date) AS "weekly&quo. datepart and timestamp, and. This is used in subquery cal to generate a list of all dates in your data. Part of AWS Collective. System date and time values are derived from the operating system of the server on which SQL Server is running. An alternative pproach is to use to_char function. However, I am trying to do a select and ignore milliseconds. 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. e. Truncate to specified precision; see Section 9. postgresql时间差计算. Truncate a date duration to the beginning of the month. In PostgreSQL, the DATE_BIN () function enables us to “bin” a timestamp into a given interval aligned with a specific origin. interval but not a specific interval like 5 minute or 5 days. PostgreSQL: truncate hour/min/second from a timestamp. It will not convert the value to a date. See Postgres Date/Time Functions and Operators for more info The simplest form of the TRUNCATE TABLE statement is as follows: The following example uses the TRUNCATE TABLE statement to delete all data from the invoices table: Besides removing data, you may want to reset the values in the identity column by using the RESTART IDENTITY option like this: For example, the following statement removes all rows. source must be a value expression of type timestamp, time, or interval. 2: date_trunc('hour', timestamp '2001-02-16 20:38:40') 2001-02-16 20:00:00:. These functions all follow a common calling convention: the first argument is the value to. 4. field selects to which precision to truncate the time stamp value. 2. SELECT TO_DATE('14 July, 2023', 'DD Month, YYYY');Welcome to the Grafana forum. Definition of PostgreSQL Trunc () PostgreSQL’s trunc () function is used to truncate the decimal places to a certain precision. In this case you still need to calculate the start date of the month you need, but that should be straight forward in any number of ways. edited Aug 18, 2015 at 10:57. . The most frequently used Postgres date functions and business scenarios where they come in handy: Rounding off timestamps with DATE_TRUNC function. 9. Oracle's DATE data type (which is what sysdate returns) always contains a time part which can not be removed. Postgres 11 adds essential functionality. This might make sense: Time: 2. Suppose the date is 4th July 2021 which is Sunday, then the date_trunc will result in. - The value for the “field” argument must be valid. Chapter 9. 31 illustrates the behaviors of the basic arithmetic operators ( +, *, etc. In this method, you ensure what the time portion is set as (or at least with far more certainty). So, for example for the users table it would be: ALTER SEQUENCE users_id_seq RESTART WITH 1. Simplify calculation of months between 2 dates (postgresql) 0. g. MySQL - Truncating Date/Time and Subtracting from Each Other. WHERE job_date >= DATE_TRUNC('month', '2019-04-01'::timestamp) If you wish to have the output as a date, append ::date: SELECT DATE_TRUNC('month', '2019-05-07'::timestamp)::date 2019-05-01 Also, note that the date converts into a timestamp as at midnight. 1 Truncate a date in Postgres (latest version) 0 PL/PGSQL function - passing a TEXT argument to date_trunc() 0 custom DATE_TRUNC timeframes. 32 shows the available functions for date/time value processing, with details appearing in the following subsections. CREATE FUNCTION TRUNC ( dttm TIMESTAMP ) RETURNS TIMESTAMP AS $$ SELECT DATE_TRUNC('DAY',$1); $$ LANGUAGE SQL IMMUTABLE; select TRUNC(NOW()::timestamp); 12. The following table lists all window functions provided by PostgreSQL. ) from a date, time, or timestamp value. Unless otherwise noted, operators shown as. The second one which use DATE_TRUNC will tranc any date to the first day of the month. 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. 2. TRUNC() function returns the result as a numeric data typeMy SQL is: SELECT date_trunc('week', '2020-06-01'::timestamp)::date ||'-'|| (date_trunc('week', '2020-06-01'::timestamp)+ '6 days'::interval)::date; However, using. DATE_TRUNC() will return an interval or timestamp rather than a number. Truncate to specified precision; see Section 9. ) field is an identifier or string that selects what field to extract. Whereas NOW () and CURRENT_TIMESTAMP give the timestamp when the transaction started. update foo set created_at = date_trunc('second', created_at) where created_at is not null; Instead of using date_trunc you can also just cast the value: created_at::timestamp(0) for the update statement, or current_timestamp::timestamp(0) in the default value. PL/pgSQL Depends on. The PostgreSQL TRUNCATE TABLE command is used to delete complete data from an existing table. To remove all data from a table, you use the DELETE statement. TRUNCATE quickly removes all rows from a set of tables. , hour, week, or month and returns the truncated timestamp or interval with a level of precision. The DATE_TRUNC() function will truncate timestamp or interval data types to return a timestamp or interval at a specified precision. Count data using multiple date. One truncates a date to the precision specified (kind of like rounding, in a way) and the other just returns a particular part of a datetime. Modified 1 year, 1 month ago. 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. 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。. The general idea is to get the current day of the week, dow, subtract 7, and take the abs, which will give you the number of days till the end of the week, and add 1, to get to Monday. I have a slow query that generates a report of account activity per week over the past year. You may be misunderstanding what date_trunc does. Syntax. 4 shows the mathematical operators that are available for the standard numeric types. It is worth noting that the function list (table 9-27) doesn't mention date_trunc(text, interval) form of date_trunc, it only lists the date_trunc(text, timestamp) version. 0. Valid formats are as follows:DATE_TRUNC() is a function used to round or truncate a timestamp to the interval you need. Practical examples would include analyzing company’s quarterly. In PostgreSQL, the TRUNCATE command is used to remove all data from a table while preserving the structure of the table. In Postgres, DATE_TRUNC () has the following intervals. PostgreSQL (and I think, SQL in general) uses "EXTRACT (EPOCH FROM ts)" to get this value. Current Date/Time. 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. SELECT (date_trunc ('MONTH', '2019-02-28'::timestamp) + INTERVAL '2 MONTH - 1 day'); Note: If you are using this in a query then you are probably better to get the first day of the following month so your query can say where xxx > month1 and xxx < followingmonth (otherwise you end up losing the last days data). date dollars 2016-10-03 1 2016-10-05 1 2016-10-10 1 2016-10-17 2 2016-10-24 2 The date_trunc(text, timestamptz) variant seems a bit under-documented, so here are my findings:. date) going over the. Table 9. In the example below, we use the select operation on the stud_cmp table to retrieve data by comparing two dates using the date_trunc function. Sorted by: 2. CURRENT_DATE関数 現在の日付を求める. Postgresql: How to find hours between 2 dates and 2 times? 3. PostgreSQL provides a number of functions that return values related to the current date and time. How can I achieve this in PostgreSQL?In PostgreSQL, the DATE_PART function is used to extract a specific element (e. 16. I have to convert a postgres query to Sequelize query. ) This function takes two arguments. 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. Avoid this, if you can. 1) number The number. source must be a value expression of type timestamp, time, or interval. When storing a date value, PostgreSQL uses the yyyy-mm-dd format e. DATE_TRUNC('datepart', timestamp) Arguments. for example 2018-10-15 will be 2018-10-01 and 2018-10-30 also will be 2018-10-01. It's not immutable because it depends on the sessions time zone setting. 2. You may create an overloaded TRUNC function in Postgresql. and while the condition is > '2018-10-01' then all dates in the month October will not be shown in the result. I changed the code in the 2nd try to be: boolean result = statement. With PostgreSQL there are a number of date/time functions available, see here. 19, earlier I have made the following Query. Below is the syntax of the TRUNCATE command:. Author: John Naylor <john. Share. This function helps in manipulating numbers as required. 9. TRUNCATE is not MVCC-safe. For formatting functions, refer to Section 9. date_trunc ('day', TIMESTAMP '2001-02-16 20:38:40+00' AT TIME ZONE 'Australia/Sydney') HTH. 61 Avg. Simply use MONTH () function. or you can create your own. 8) Postgres DATE_TRUNC() Function. select current_time - interval '1' hour. 19, earlier I have made the following Query. This is an excerpt from my sql query. 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. 0 Replicate Oracle's `TRUNC(DATE, 'WW')` behaviour in PostgreSQL. Table 10-4. 0. 0.