TIMESTAMPDIFF¶
TIMESTAMPDIFF(unit, timestamp_val1, timestamp_val2)
Returns the amount of time that has passed since timestamp_val1 until
timestamp_val2 in terms of the unit specified, ignoring all smaller units.
E.g., December 31 of 2020 and January 1 of 2021 count as 1 year apart.
Note
For all units larger than NANOSECOND, the output type is INTEGER
instead of BIGINT, so any difference values that cannot be stored as
signed 32-bit integers might not be returned correct.