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Fonctions de date et d’heure

TIMESTAMPDIFF

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

Alternative pour DATEDIFF.

Syntaxe

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

Arguments

date_or_time_part

The unit of time. Must be one of the values listed in Parties de date et d’heure prises en charge (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.

Returns

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

Notes sur l’utilisation

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

  • 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 doit être l’une des valeurs répertoriées dans Parties de date et d’heure prises en charge.

    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 Semaines civiles et jours de semaine.

  • 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.

Exemples

For example(s), see DATEDIFF. (DATEDIFF, TIMEDIFF, and TIMESTAMPDIFF all use the same basic format.)

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