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What is the difference between DATESPAN and DATEDIFF operators?


DATESPAN calculates the time duration between two dates based on specified intervals, such as days, weeks, or months. It provides the duration within these intervals and is ideal for scenarios where you need to measure time in meaningful units.

For instance, if you want to know the time gap between two events in days or months, DATESPAN is the go-to operator.

Example: Consider two dates - 2023-01-01 23:59, and 2023-01-03 00:00. Using DATESPAN with a day interval, you'd get a result of 1 day, emphasizing the specific interval.

Another example: If you choose a month as the interval, the same two dates will yield a result of 0 months, focusing on the month-level duration.


DATEDIFF, on the other hand, computes the absolute difference between two dates in terms of the specified interval type, like days, months, or years. It's useful when you need a precise count of these units between two dates, disregarding the specific intervals.

For instance, to determine the exact number of days between two dates, DATEDIFF provides this precise difference.

Example: If you choose months as the interval, and the dates are 2023-01-01 and 2023-03-01, DATEDIFF would yield 2 months, reflecting the month-level difference.

In summary, DATESPAN is ideal for measuring time in specified intervals, providing the duration within those intervals (e.g., days, months). DATEDIFF, however, offers the absolute difference between dates in terms of the specified interval type (e.g., days, months), disregarding specific intervals.