On Monday, October 11, 2021, Zhihong Zhang <
zhihong@gmail.com> wrote:
They are several days apart. Maybe leap years are not counted properly?
That is related. Intervals supply integer years, months, and days (for example). Given an integer month (or year) value there is no way to accurately compute the number of days involved (or any subfield of day) since you lack knowledge of which months (years) they are (generally). So extracting an epoch from an interval is an inherently unwise thing to do. Having done it, comparing its result to a timestamp epoch computation is meaningless. If you can do the later then just do it as it will provide the expected answer while the interval epoch is inherently problematic.
David J.