Table 9.32 shows the available
   functions for date/time value processing, with details appearing in
   the following subsections.  Table 9.31 illustrates the behaviors of
   the basic arithmetic operators (+,
   *, etc.).  For formatting functions, refer to
   Section 9.8.  You should be familiar with
   the background information on date/time data types from Section 8.5.
  
   In addition, the usual comparison operators shown in
   Table 9.1 are available for the
   date/time types.  Dates and timestamps (with or without time zone) are
   all comparable, while times (with or without time zone) and intervals
   can only be compared to other values of the same data type.  When
   comparing a timestamp without time zone to a timestamp with time zone,
   the former value is assumed to be given in the time zone specified by
   the TimeZone configuration parameter, and is
   rotated to UTC for comparison to the latter value (which is already
   in UTC internally).  Similarly, a date value is assumed to represent
   midnight in the TimeZone zone when comparing it
   to a timestamp.
  
   All the functions and operators described below that take time or timestamp
   inputs actually come in two variants: one that takes time with time zone or timestamp
   with time zone, and one that takes time without time zone or timestamp without time zone.
   For brevity, these variants are not shown separately.  Also, the
   + and * operators come in commutative pairs (for
   example both date + integer
   and integer + date); we show
   only one of each such pair.
  
Table 9.31. Date/Time Operators
| Operator Description Example(s) | 
|---|
| 
          Add a number of days to a date 
          | 
| 
          Add an interval to a date 
          | 
| 
          Add a time-of-day to a date 
          | 
| 
          Add intervals 
          | 
| 
          Add an interval to a timestamp 
          | 
| 
          Add an interval to a time 
          | 
| 
          Negate an interval 
          | 
| 
          Subtract dates, producing the number of days elapsed 
          | 
| 
          Subtract a number of days from a date 
          | 
| 
          Subtract an interval from a date 
          | 
| 
          Subtract times 
          | 
| 
          Subtract an interval from a time 
          | 
| 
          Subtract an interval from a timestamp 
          | 
| 
          Subtract intervals 
          | 
| 
          
         Subtract timestamps (converting 24-hour intervals into days,
         similarly to  
          | 
| 
          Multiply an interval by a scalar 
          
          
          | 
| 
          Divide an interval by a scalar 
          | 
Table 9.32. Date/Time Functions
| Function Description Example(s) | 
|---|
| 
         
          Subtract arguments, producing a “symbolic” result that uses years and months, rather than just days 
          | 
| 
          
         Subtract argument from  
          | 
| 
         
          Current date and time (changes during statement execution); see Section 9.9.4 
          | 
| Current date; see Section 9.9.4 
          | 
| 
         
          Current time of day; see Section 9.9.4 
          | 
| 
          Current time of day, with limited precision; see Section 9.9.4 
          | 
| 
         
          Current date and time (start of current transaction); see Section 9.9.4 
          | 
| 
          Current date and time (start of current transaction), with limited precision; see Section 9.9.4 
          | 
| 
         
          
         Get timestamp subfield (equivalent to  
          | 
| 
          
         Get interval subfield (equivalent to  
          | 
| 
         
          Truncate to specified precision; see Section 9.9.2 
          | 
| 
          Truncate to specified precision in the specified time zone; see Section 9.9.2 
          | 
| 
          Truncate to specified precision; see Section 9.9.2 
          | 
| 
         
          Get timestamp subfield; see Section 9.9.1 
          | 
| 
          Get interval subfield; see Section 9.9.1 
          | 
| Test for finite date (not +/-infinity) 
          | 
| 
          Test for finite timestamp (not +/-infinity) 
          | 
| 
          Test for finite interval (currently always true) 
          | 
| 
         
          Adjust interval, converting 30-day time periods to months 
          | 
| 
         
          Adjust interval, converting 24-hour time periods to days 
          | 
| 
         
          
         Adjust interval using  
          | 
| Current time of day; see Section 9.9.4 
          | 
| 
          Current time of day, with limited precision; see Section 9.9.4 
          | 
| Current date and time (start of current transaction); see Section 9.9.4 
          | 
| 
          Current date and time (start of current transaction), with limited precision; see Section 9.9.4 
          | 
| 
         
          Create date from year, month and day fields 
          | 
| 
          Create interval from years, months, weeks, days, hours, minutes and seconds fields, each of which can default to zero 
          | 
| 
         
          Create time from hour, minute and seconds fields 
          | 
| 
         
          Create timestamp from year, month, day, hour, minute and seconds fields 
          | 
| 
         
          
         Create timestamp with time zone from year, month, day, hour, minute
         and seconds fields; if  
          | 
| 
         
          Current date and time (start of current transaction); see Section 9.9.4 
          | 
| 
         
          Current date and time (start of current statement); see Section 9.9.4 
          | 
| 
         Current date and time
         (like  
          | 
| 
         
          Current date and time (start of current transaction); see Section 9.9.4 
          | 
| 
         
          Convert Unix epoch (seconds since 1970-01-01 00:00:00+00) to timestamp with time zone 
          | 
    
    In addition to these functions, the SQL OVERLAPS operator is
    supported:
(start1,end1) OVERLAPS (start2,end2) (start1,length1) OVERLAPS (start2,length2)
    This expression yields true when two time periods (defined by their
    endpoints) overlap, false when they do not overlap.  The endpoints
    can be specified as pairs of dates, times, or time stamps; or as
    a date, time, or time stamp followed by an interval.  When a pair
    of values is provided, either the start or the end can be written
    first; OVERLAPS automatically takes the earlier value
    of the pair as the start.  Each time period is considered to
    represent the half-open interval start <=
    time < end, unless
    start and end are equal in which case it
    represents that single time instant.  This means for instance that two
    time periods with only an endpoint in common do not overlap.
   
SELECT (DATE '2001-02-16', DATE '2001-12-21') OVERLAPS
       (DATE '2001-10-30', DATE '2002-10-30');
Result: true
SELECT (DATE '2001-02-16', INTERVAL '100 days') OVERLAPS
       (DATE '2001-10-30', DATE '2002-10-30');
Result: false
SELECT (DATE '2001-10-29', DATE '2001-10-30') OVERLAPS
       (DATE '2001-10-30', DATE '2001-10-31');
Result: false
SELECT (DATE '2001-10-30', DATE '2001-10-30') OVERLAPS
       (DATE '2001-10-30', DATE '2001-10-31');
Result: true
   When adding an interval value to (or subtracting an
   interval value from) a timestamp with time zone
   value, the days component advances or decrements the date of the
   timestamp with time zone by the indicated number of days,
   keeping the time of day the same.
   Across daylight saving time changes (when the session time zone is set to a
   time zone that recognizes DST), this means interval '1 day'
   does not necessarily equal interval '24 hours'.
   For example, with the session time zone set
   to America/Denver:
SELECT timestamp with time zone '2005-04-02 12:00:00-07' + interval '1 day'; Result:2005-04-03 12:00:00-06SELECT timestamp with time zone '2005-04-02 12:00:00-07' + interval '24 hours'; Result:2005-04-03 13:00:00-06
   This happens because an hour was skipped due to a change in daylight saving
   time at 2005-04-03 02:00:00 in time zone
   America/Denver.
  
   Note there can be ambiguity in the months field returned by
   age because different months have different numbers of
   days.  PostgreSQL's approach uses the month from the
   earlier of the two dates when calculating partial months.  For example,
   age('2004-06-01', '2004-04-30') uses April to yield
   1 mon 1 day, while using May would yield 1 mon 2
   days because May has 31 days, while April has only 30.
  
   Subtraction of dates and timestamps can also be complex.  One conceptually
   simple way to perform subtraction is to convert each value to a number
   of seconds using EXTRACT(EPOCH FROM ...), then subtract the
   results; this produces the
   number of seconds between the two values.  This will adjust
   for the number of days in each month, timezone changes, and daylight
   saving time adjustments.  Subtraction of date or timestamp
   values with the “-” operator
   returns the number of days (24-hours) and hours/minutes/seconds
   between the values, making the same adjustments.  The age
   function returns years, months, days, and hours/minutes/seconds,
   performing field-by-field subtraction and then adjusting for negative
   field values.  The following queries illustrate the differences in these
   approaches.  The sample results were produced with timezone
   = 'US/Eastern'; there is a daylight saving time change between the
   two dates used:
  
SELECT EXTRACT(EPOCH FROM timestamptz '2013-07-01 12:00:00') -
       EXTRACT(EPOCH FROM timestamptz '2013-03-01 12:00:00');
Result: 10537200
SELECT (EXTRACT(EPOCH FROM timestamptz '2013-07-01 12:00:00') -
        EXTRACT(EPOCH FROM timestamptz '2013-03-01 12:00:00'))
        / 60 / 60 / 24;
Result: 121.958333333333
SELECT timestamptz '2013-07-01 12:00:00' - timestamptz '2013-03-01 12:00:00';
Result: 121 days 23:00:00
SELECT age(timestamptz '2013-07-01 12:00:00', timestamptz '2013-03-01 12:00:00');
Result: 4 mons
EXTRACT, date_partEXTRACT(fieldFROMsource)
    The extract function retrieves subfields
    such as year or hour from date/time values.
    source must be a value expression of
    type timestamp, date, time,
    or interval.  (Timestamps and times can be with or
    without time zone.)
    field is an identifier or
    string that selects what field to extract from the source value.
    Not all fields are valid for every input data type; for example, fields
    smaller than a day cannot be extracted from a date, while
    fields of a day or more cannot be extracted from a time.
    The extract function returns values of type
    double precision.
   
The following are valid field names:
century
        The century; for interval values, the year field
        divided by 100
       
SELECT EXTRACT(CENTURY FROM TIMESTAMP '2000-12-16 12:21:13'); Result:20SELECT EXTRACT(CENTURY FROM TIMESTAMP '2001-02-16 20:38:40'); Result:21SELECT EXTRACT(CENTURY FROM DATE '0001-01-01 AD'); Result:1SELECT EXTRACT(CENTURY FROM DATE '0001-12-31 BC'); Result:-1SELECT EXTRACT(CENTURY FROM INTERVAL '2001 years'); Result:20
day
        The day of the month (1–31); for interval
        values, the number of days
       
SELECT EXTRACT(DAY FROM TIMESTAMP '2001-02-16 20:38:40'); Result:16SELECT EXTRACT(DAY FROM INTERVAL '40 days 1 minute'); Result:40
decadeThe year field divided by 10
SELECT EXTRACT(DECADE FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 200
dow
        The day of the week as Sunday (0) to
        Saturday (6)
       
SELECT EXTRACT(DOW FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 5
        Note that extract's day of the week numbering
        differs from that of the to_char(...,
        'D') function.
       
doyThe day of the year (1–365/366)
SELECT EXTRACT(DOY FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 47
epoch
        For timestamp with time zone values, the
        number of seconds since 1970-01-01 00:00:00 UTC (negative for
        timestamps before that);
        for date and timestamp values, the
        nominal number of seconds since 1970-01-01 00:00:00,
        without regard to timezone or daylight-savings rules;
        for interval values, the total number
        of seconds in the interval
       
SELECT EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40.12-08'); Result:982384720.12SELECT EXTRACT(EPOCH FROM TIMESTAMP '2001-02-16 20:38:40.12'); Result:982355920.12SELECT EXTRACT(EPOCH FROM INTERVAL '5 days 3 hours'); Result:442800
        You can convert an epoch value back to a timestamp with time zone
        with to_timestamp:
       
SELECT to_timestamp(982384720.12);
Result: 2001-02-17 04:38:40.12+00
        Beware that applying to_timestamp to an epoch
        extracted from a date or timestamp value
        could produce a misleading result: the result will effectively
        assume that the original value had been given in UTC, which might
        not be the case.
       
hourThe hour field (0–23 in timestamps, unrestricted in intervals)
SELECT EXTRACT(HOUR FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 20
isodow
        The day of the week as Monday (1) to
        Sunday (7)
       
SELECT EXTRACT(ISODOW FROM TIMESTAMP '2001-02-18 20:38:40');
Result: 7
        This is identical to dow except for Sunday.  This
        matches the ISO 8601 day of the week numbering.
       
isoyearThe ISO 8601 week-numbering year that the date falls in
SELECT EXTRACT(ISOYEAR FROM DATE '2006-01-01'); Result:2005SELECT EXTRACT(ISOYEAR FROM DATE '2006-01-02'); Result:2006
        Each ISO 8601 week-numbering year begins with the
        Monday of the week containing the 4th of January, so in early
        January or late December the ISO year may be
        different from the Gregorian year.  See the week
        field for more information.
       
julianThe Julian Date corresponding to the date or timestamp. Timestamps that are not local midnight result in a fractional value. See Section B.7 for more information.
SELECT EXTRACT(JULIAN FROM DATE '2006-01-01'); Result:2453737SELECT EXTRACT(JULIAN FROM TIMESTAMP '2006-01-01 12:00'); Result:2453737.5
microsecondsThe seconds field, including fractional parts, multiplied by 1 000 000; note that this includes full seconds
SELECT EXTRACT(MICROSECONDS FROM TIME '17:12:28.5');
Result: 28500000
millennium
        The millennium; for interval values, the year field
        divided by 1000
       
SELECT EXTRACT(MILLENNIUM FROM TIMESTAMP '2001-02-16 20:38:40'); Result:3SELECT EXTRACT(MILLENNIUM FROM INTERVAL '2001 years'); Result:2
Years in the 1900s are in the second millennium. The third millennium started January 1, 2001.
millisecondsThe seconds field, including fractional parts, multiplied by 1000. Note that this includes full seconds.
SELECT EXTRACT(MILLISECONDS FROM TIME '17:12:28.5');
Result: 28500
minuteThe minutes field (0–59)
SELECT EXTRACT(MINUTE FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 38
month
        The number of the month within the year (1–12);
        for interval values, the number of months modulo 12
        (0–11)
       
SELECT EXTRACT(MONTH FROM TIMESTAMP '2001-02-16 20:38:40'); Result:2SELECT EXTRACT(MONTH FROM INTERVAL '2 years 3 months'); Result:3SELECT EXTRACT(MONTH FROM INTERVAL '2 years 13 months'); Result:1
quarterThe quarter of the year (1–4) that the date is in
SELECT EXTRACT(QUARTER FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 1
secondThe seconds field, including any fractional seconds
SELECT EXTRACT(SECOND FROM TIMESTAMP '2001-02-16 20:38:40'); Result:40SELECT EXTRACT(SECOND FROM TIME '17:12:28.5'); Result:28.5
timezoneThe time zone offset from UTC, measured in seconds. Positive values correspond to time zones east of UTC, negative values to zones west of UTC. (Technically, PostgreSQL does not use UTC because leap seconds are not handled.)
timezone_hourThe hour component of the time zone offset
timezone_minuteThe minute component of the time zone offset
weekThe number of the ISO 8601 week-numbering week of the year. By definition, ISO weeks start on Mondays and the first week of a year contains January 4 of that year. In other words, the first Thursday of a year is in week 1 of that year.
        In the ISO week-numbering system, it is possible for early-January
        dates to be part of the 52nd or 53rd week of the previous year, and for
        late-December dates to be part of the first week of the next year.
        For example, 2005-01-01 is part of the 53rd week of year
        2004, and 2006-01-01 is part of the 52nd week of year
        2005, while 2012-12-31 is part of the first week of 2013.
        It's recommended to use the isoyear field together with
        week to get consistent results.
       
SELECT EXTRACT(WEEK FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 7
year
        The year field.  Keep in mind there is no 0 AD, so subtracting
        BC years from AD years should be done with care.
       
SELECT EXTRACT(YEAR FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 2001
    When processing an interval value,
    the extract function produces field values that
    match the interpretation used by the interval output function.  This
    can produce surprising results if one starts with a non-normalized
    interval representation, for example:
SELECT INTERVAL '80 minutes'; Result:01:20:00SELECT EXTRACT(MINUTES FROM INTERVAL '80 minutes'); Result:20
     When the input value is +/-Infinity, extract returns
     +/-Infinity for monotonically-increasing fields (epoch,
     julian, year, isoyear,
     decade, century, and millennium).
     For other fields, NULL is returned.  PostgreSQL
     versions before 9.6 returned zero for all cases of infinite input.
    
    The extract function is primarily intended
    for computational processing.  For formatting date/time values for
    display, see Section 9.8.
   
    The date_part function is modeled on the traditional
    Ingres equivalent to the
    SQL-standard function extract:
date_part('field', source)
    Note that here the field parameter needs to
    be a string value, not a name.  The valid field names for
    date_part are the same as for
    extract.
   
SELECT date_part('day', TIMESTAMP '2001-02-16 20:38:40');
Result: 16
SELECT date_part('hour', INTERVAL '4 hours 3 minutes');
Result: 4
date_trunc
    The function date_trunc is conceptually
    similar to the trunc function for numbers.
   
date_trunc(field,source[,time_zone])
    source is a value expression of type
    timestamp, timestamp with time zone,
    or interval.
    (Values of type date and
    time are cast automatically to timestamp or
    interval, respectively.)
    field selects to which precision to
    truncate the input value.  The return value is likewise of type
    timestamp, timestamp with time zone,
    or interval,
    and it has all fields that are less significant than the
    selected one set to zero (or one, for day and month).
   
    Valid values for field are:
    
| microseconds | 
| milliseconds | 
| second | 
| minute | 
| hour | 
| day | 
| week | 
| month | 
| quarter | 
| year | 
| decade | 
| century | 
| millennium | 
    When the input value is of type timestamp with time zone,
    the truncation is performed with respect to a particular time zone;
    for example, truncation to day produces a value that
    is midnight in that zone.  By default, truncation is done with respect
    to the current TimeZone setting, but the
    optional time_zone argument can be provided
    to specify a different time zone.  The time zone name can be specified
    in any of the ways described in Section 8.5.3.
   
    A time zone cannot be specified when processing timestamp without
    time zone or interval inputs.  These are always
    taken at face value.
   
    Examples (assuming the local time zone is America/New_York):
SELECT date_trunc('hour', TIMESTAMP '2001-02-16 20:38:40');
Result: 2001-02-16 20:00:00
SELECT date_trunc('year', TIMESTAMP '2001-02-16 20:38:40');
Result: 2001-01-01 00:00:00
SELECT date_trunc('day', TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40+00');
Result: 2001-02-16 00:00:00-05
SELECT date_trunc('day', TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40+00', 'Australia/Sydney');
Result: 2001-02-16 08:00:00-05
SELECT date_trunc('hour', INTERVAL '3 days 02:47:33');
Result: 3 days 02:00:00
AT TIME ZONE
    The AT TIME ZONE operator converts time
    stamp without time zone to/from
    time stamp with time zone, and
    time with time zone values to different time
    zones. Table 9.33 shows its
    variants.
   
Table 9.33. AT TIME ZONE Variants
| Operator Description Example(s) | 
|---|
| 
          Converts given time stamp without time zone to time stamp with time zone, assuming the given value is in the named time zone. 
          | 
| 
          Converts given time stamp with time zone to time stamp without time zone, as the time would appear in that zone. 
          | 
| 
          Converts given time with time zone to a new time zone. Since no date is supplied, this uses the currently active UTC offset for the named destination zone. 
          | 
    In these expressions, the desired time zone zone can be
    specified either as a text value (e.g., 'America/Los_Angeles')
    or as an interval (e.g., INTERVAL '-08:00').
    In the text case, a time zone name can be specified in any of the ways
    described in Section 8.5.3.
    The interval case is only useful for zones that have fixed offsets from
    UTC, so it is not very common in practice.
   
    Examples (assuming the current TimeZone setting
    is America/Los_Angeles):
SELECT TIMESTAMP '2001-02-16 20:38:40' AT TIME ZONE 'America/Denver'; Result:2001-02-16 19:38:40-08SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'America/Denver'; Result:2001-02-16 18:38:40SELECT TIMESTAMP '2001-02-16 20:38:40' AT TIME ZONE 'Asia/Tokyo' AT TIME ZONE 'America/Chicago'; Result:2001-02-16 05:38:40
    The first example adds a time zone to a value that lacks it, and
    displays the value using the current TimeZone
    setting.  The second example shifts the time stamp with time zone value
    to the specified time zone, and returns the value without a time zone.
    This allows storage and display of values different from the current
    TimeZone setting.  The third example converts
    Tokyo time to Chicago time.
   
    The function timezone(zone,
    timestamp)timestamp AT TIME ZONE
    zone
PostgreSQL provides a number of functions that return values related to the current date and time. These SQL-standard functions all return values based on the start time of the current transaction:
CURRENT_DATE CURRENT_TIME CURRENT_TIMESTAMP CURRENT_TIME(precision) CURRENT_TIMESTAMP(precision) LOCALTIME LOCALTIMESTAMP LOCALTIME(precision) LOCALTIMESTAMP(precision)
     CURRENT_TIME and
     CURRENT_TIMESTAMP deliver values with time zone;
     LOCALTIME and
     LOCALTIMESTAMP deliver values without time zone.
    
     CURRENT_TIME,
     CURRENT_TIMESTAMP,
     LOCALTIME, and
     LOCALTIMESTAMP
     can optionally take
     a precision parameter, which causes the result to be rounded
     to that many fractional digits in the seconds field.  Without a precision parameter,
     the result is given to the full available precision.
    
Some examples:
SELECT CURRENT_TIME; Result:14:39:53.662522-05SELECT CURRENT_DATE; Result:2019-12-23SELECT CURRENT_TIMESTAMP; Result:2019-12-23 14:39:53.662522-05SELECT CURRENT_TIMESTAMP(2); Result:2019-12-23 14:39:53.66-05SELECT LOCALTIMESTAMP; Result:2019-12-23 14:39:53.662522
Since these functions return the start time of the current transaction, their values do not change during the transaction. This is considered a feature: the intent is to allow a single transaction to have a consistent notion of the “current” time, so that multiple modifications within the same transaction bear the same time stamp.
Other database systems might advance these values more frequently.
PostgreSQL also provides functions that return the start time of the current statement, as well as the actual current time at the instant the function is called. The complete list of non-SQL-standard time functions is:
transaction_timestamp() statement_timestamp() clock_timestamp() timeofday() now()
    transaction_timestamp() is equivalent to
    CURRENT_TIMESTAMP, but is named to clearly reflect
    what it returns.
    statement_timestamp() returns the start time of the current
    statement (more specifically, the time of receipt of the latest command
    message from the client).
    statement_timestamp() and transaction_timestamp()
    return the same value during the first command of a transaction, but might
    differ during subsequent commands.
    clock_timestamp() returns the actual current time, and
    therefore its value changes even within a single SQL command.
    timeofday() is a historical
    PostgreSQL function.  Like
    clock_timestamp(), it returns the actual current time,
    but as a formatted text string rather than a timestamp
    with time zone value.
    now() is a traditional PostgreSQL
    equivalent to transaction_timestamp().
   
    All the date/time data types also accept the special literal value
    now to specify the current date and time (again,
    interpreted as the transaction start time).  Thus,
    the following three all return the same result:
SELECT CURRENT_TIMESTAMP; SELECT now(); SELECT TIMESTAMP 'now'; -- but see tip below
      Do not use the third form when specifying a value to be evaluated later,
      for example in a DEFAULT clause for a table column.
      The system will convert now
      to a timestamp as soon as the constant is parsed, so that when
      the default value is needed,
      the time of the table creation would be used!  The first two
      forms will not be evaluated until the default value is used,
      because they are function calls.  Thus they will give the desired
      behavior of defaulting to the time of row insertion.
      (See also Section 8.5.1.4.)
     
The following functions are available to delay execution of the server process:
pg_sleep (double precision) pg_sleep_for (interval) pg_sleep_until (timestamp with time zone)
    pg_sleep makes the current session's process
    sleep until the given number of seconds have
    elapsed.  Fractional-second delays can be specified.
    pg_sleep_for is a convenience function to
    allow the sleep time to be specified as an interval.
    pg_sleep_until is a convenience function for when
    a specific wake-up time is desired.
    For example:
SELECT pg_sleep(1.5);
SELECT pg_sleep_for('5 minutes');
SELECT pg_sleep_until('tomorrow 03:00');
      The effective resolution of the sleep interval is platform-specific;
      0.01 seconds is a common value.  The sleep delay will be at least as long
      as specified. It might be longer depending on factors such as server load.
      In particular, pg_sleep_until is not guaranteed to
      wake up exactly at the specified time, but it will not wake up any earlier.
     
      Make sure that your session does not hold more locks than necessary
      when calling pg_sleep or its variants.  Otherwise
      other sessions might have to wait for your sleeping process, slowing down
      the entire system.