Kinh Nghiệm Hướng dẫn To calculate the difference between two date columns, you must use the to_date function. 2022
Hà Huy Tùng Nguyên đang tìm kiếm từ khóa To calculate the difference between two date columns, you must use the to_date function. được Cập Nhật vào lúc : 2022-10-30 07:58:06 . Với phương châm chia sẻ Mẹo về trong nội dung bài viết một cách Chi Tiết 2022. Nếu sau khi đọc tài liệu vẫn ko hiểu thì hoàn toàn có thể lại Comment ở cuối bài để Mình lý giải và hướng dẫn lại nha.Categories:
Date & Time Functions
Nội dung chính Show- Arguments¶Usage Notes¶Which of the following functions is used to determine the number of months between two date values?When a format argument is included in a function it must be enclosed in ____?Which of the following functions can be used to convert a character string to upper case letters?When functions are nested the outer function is solved or executed first?
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(For minus sign
Arguments¶
For DATEDIFF:
date_or_time_partThe 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_expr2The 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_expr2The 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, 2022 and February 28, 2022 is closer to two months than to one month, the following returns one month:
DATEDIFF(month, '2022-01-01'::DATE, '2022-02-28'::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', '2022-01-01'), ('2022-01-01', '2022-12-31'), ('2022-08-23', '2022-09-07'); +------------+------------+------------+-------------+-----------+---------------------+ | 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 | 2022-01-01 | 1 | 1 | 1 | 1 | | 2022-01-01 | 2022-12-31 | 1 | 23 | 730 | 730 | | 2022-08-23 | 2022-09-07 | 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 ('2022-01-01 01:59:59'::TIMESTAMP, '2022-01-01 02:00:00'::TIMESTAMP), ('2022-01-01 01:00:00'::TIMESTAMP, '2022-01-01 01:59:00'::TIMESTAMP), ('2022-01-01 01:00:59'::TIMESTAMP, '2022-01-01 02:00:00'::TIMESTAMP); +---------------------------+---------------------------+------------+--------------+--------------+ | TIMESTAMP_1 | TIMESTAMP_2 | DIFF_HOURS | DIFF_MINUTES | DIFF_SECONDS | |---------------------------+---------------------------+------------+--------------+--------------| | Fri, 01 Jan 2022 01:59:59 | Fri, 01 Jan 2022 02:00:00 | 1 | 1 | 1 | | Fri, 01 Jan 2022 01:00:00 | Fri, 01 Jan 2022 01:59:00 | 0 | 59 | 3540 | | Fri, 01 Jan 2022 01:00:59 | Fri, 01 Jan 2022 02:00:00 | 1 | 60 | 3541 | +---------------------------+---------------------------+------------+--------------+--------------+Which of the following functions is used to determine the number of months between two date values?
You can use the DateDiff function to determine how many specified time intervals exist between two dates.When a format argument is included in a function it must be enclosed in ____?
All arguments must be enclosed by parentheses.Which of the following functions can be used to convert a character string to upper case letters?
The toUpperCase() method returns the value of the string converted to uppercase.When functions are nested the outer function is solved or executed first?
When functions are nested, the inner function is solved first. The TRUNC function can be used to add insignificant zeros to the right of a decimal point for numeric data. Single-row functions return one row of results for each group or category of rows processed. Tải thêm tài liệu liên quan đến nội dung bài viết To calculate the difference between two date columns, you must use the to_date function.