Categories:

Date & Time Functions

DATEDIFF

Calculates the difference between two date, time, or timestamp expressions based on the date or time part requested. The function returns the result of subtracting the second argument from the third argument.

The minus sign (-) can also be used to subtract dates.

See also:

TIMEDIFF , TIMESTAMPDIFF

Syntax

For DATEDIFF

DATEDIFF( <date_or_time_part>, <date_or_time_expr1>, <date_or_time_expr2> )

For minus sign

<date_expr2> - <date_expr1>

Arguments

For DATEDIFF:

date_or_time_part

The unit of time. Must be one of the values listed in Supported Date and Time Parts (e.g. month). The value can be a string literal or can be unquoted (e.g. 'month' or month).

date_or_time_expr1, date_or_time_expr2

The values to compare. Must be a date, a time, a timestamp, or an expression that can be evaluated to a date, a time, or a timestamp. The value date_or_time_expr1 is subtracted from date_or_time_expr2.

For minus sign:

date_expr1, date_expr2

The values to compare. Must be a date, or an expression that can be evaluated to a date. The value date_expr1 is subtracted from date_expr2.

Returns

For DATEDIFF:

Returns an integer representing the number of units (seconds, days, etc.) difference between date_or_time_expr2 and date_or_time_expr1.

For minus sign:

Returns an integer representing the number of days difference between date_expr2 and date_expr1. (The units are always days.)

Usage Notes

For both DATEDIFF and minus sign:

  • Output values can be negative, for example, -12 days.

For DATEDIFF:

  • date_or_time_expr1 and date_or_time_expr2 can be a date, time, or timestamp.

  • The function supports units of years, quarters, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, and nanoseconds.

  • date_or_time_part must be one of the values listed in Supported Date and Time Parts.

    If date_or_time_part is week (or any of its variations), the output is controlled by the WEEK_START session parameter. For more details, including examples, see Calendar Weeks and Weekdays.

  • The unit (e.g. month) used to calculate the difference determines which parts of the DATE, TIME, or TIMESTAMP field are used to determine the result and thus determines the precision of the result.

    Smaller units are not used, so values are not rounded. For example, even though the difference between January 1, 2021 and February 28, 2021 is closer to two months than to one month, the following returns one month:

    DATEDIFF(month, '2021-01-01'::DATE, '2021-02-28'::DATE)
    

    For a DATE value:

    • year uses only the year and disregards all the other parts.

    • month uses the month and year.

    • day uses the entire date.

    For a TIME value:

    • hour uses only the hour and disregards all the other parts.

    • minute uses the hour and minute.

    • second uses the hour, minute, and second, but not the fractional seconds.

    • millisecond uses the hour, minute, second, and first three digits of the fractional seconds. Fractional seconds are not rounded. For example, DATEDIFF(milliseconds, '00:00:00', '00:00:01.1239') returns 1.123 seconds, not 1.124 seconds.

    • microsecond uses the hour, minute, second, and first six digits of the fractional seconds. Fractional seconds are not rounded.

    • nanosecond uses the hour, minute, second, and all nine digits of the fractional seconds.

    For a TIMESTAMP value:

    The rules match the rules for DATE and TIME data types above. Only the specified unit and larger units are used.

For minus sign:

  • date_expr1 and date_expr2 must both be dates. Times and timestamps are not allowed.

Examples

Calculate the difference in years between two timestamps:

SELECT DATEDIFF(year, '2010-04-09 14:39:20'::TIMESTAMP, 
                      '2013-05-08 23:39:20'::TIMESTAMP) 
               AS diff_years;
+------------+
| DIFF_YEARS |
|------------|
|          3 |
+------------+

Calculate the difference in hours between two timestamps:

SELECT DATEDIFF(hour, '2013-05-08T23:39:20.123-07:00'::TIMESTAMP, 
    DATEADD(year, 2, ('2013-05-08T23:39:20.123-07:00')::TIMESTAMP)) 
               AS diff_hours;
+------------+
| DIFF_HOURS |
|------------|
|      17520 |
+------------+

Demonstrate how date parts affect DATEDIFF calculations; also, demonstrate use of the minus sign for date subtraction:

SELECT column1 date_1, column2 date_2,
      DATEDIFF(year, column1, column2) diff_years,
      DATEDIFF(month, column1, column2) diff_months,
      DATEDIFF(day, column1, column2) diff_days,
      column2::DATE - column1::DATE AS diff_days_via_minus
    FROM VALUES
      ('2015-12-30', '2015-12-31'),
      ('2015-12-31', '2016-01-01'),
      ('2016-01-01', '2017-12-31'),
      ('2016-08-23', '2016-09-07');
+------------+------------+------------+-------------+-----------+---------------------+
| DATE_1     | DATE_2     | DIFF_YEARS | DIFF_MONTHS | DIFF_DAYS | DIFF_DAYS_VIA_MINUS |
|------------+------------+------------+-------------+-----------+---------------------|
| 2015-12-30 | 2015-12-31 |          0 |           0 |         1 |                   1 |
| 2015-12-31 | 2016-01-01 |          1 |           1 |         1 |                   1 |
| 2016-01-01 | 2017-12-31 |          1 |          23 |       730 |                 730 |
| 2016-08-23 | 2016-09-07 |          0 |           1 |        15 |                  15 |
+------------+------------+------------+-------------+-----------+---------------------+

Demonstrate how time parts affect DATEDIFF calculations:

ALTER SESSION SET TIMESTAMP_NTZ_OUTPUT_FORMAT = 'DY, DD MON YYYY HH24:MI:SS';
SELECT column1 timestamp_1, column2 timestamp_2,
      DATEDIFF(hour, column1, column2) diff_hours,
      DATEDIFF(minute, column1, column2) diff_minutes,
      DATEDIFF(second, column1, column2) diff_seconds
    FROM VALUES
      ('2016-01-01 01:59:59'::TIMESTAMP, '2016-01-01 02:00:00'::TIMESTAMP),
      ('2016-01-01 01:00:00'::TIMESTAMP, '2016-01-01 01:59:00'::TIMESTAMP),
      ('2016-01-01 01:00:59'::TIMESTAMP, '2016-01-01 02:00:00'::TIMESTAMP);
+---------------------------+---------------------------+------------+--------------+--------------+
| TIMESTAMP_1               | TIMESTAMP_2               | DIFF_HOURS | DIFF_MINUTES | DIFF_SECONDS |
|---------------------------+---------------------------+------------+--------------+--------------|
| Fri, 01 Jan 2016 01:59:59 | Fri, 01 Jan 2016 02:00:00 |          1 |            1 |            1 |
| Fri, 01 Jan 2016 01:00:00 | Fri, 01 Jan 2016 01:59:00 |          0 |           59 |         3540 |
| Fri, 01 Jan 2016 01:00:59 | Fri, 01 Jan 2016 02:00:00 |          1 |           60 |         3541 |
+---------------------------+---------------------------+------------+--------------+--------------+
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