具有特定条件时间开始和时间结束的 Date_diff

Question

is it possible to have date_diff with specific start and end time?

let say my store are open from 8AM - 10PM, which is 14 Hours. and I have a lot of stuff to sell during that time. One of the SKU is out of stock from 2022-11-01 06.00 PM until tomorrow 2022-11-02 11.00 AM.

Instead of calculate 24 hours, I just want to calculate only from opening store until it closed or until its restock. Meaning from 6PM to 11AM is 8 Hours

my query

select date_diff('2022-11-02 11.00 AM', '2022-11-02 06.00 PM', hour) from table

with the result 17 hours instead of 8 hours

Answer 1

There isn't a way to configure DATE_DIFF to do this for you, but it's possible to do what you want, with some effort .

You should convert your dates to timestamps ( TIMESTAMP(yourdate) or CAST(yourdate AS TIMESTAMP) ) and use TIMESTAMP_DIFF instead.

This will allow you to work with smaller intervals than days.

For your calculation, you ultimately need to find the total time difference between the two timestamps and then subtract the out-of-hours timeframe.

However, calculating the latter is not as simple as taking the difference in days and multiplying by 8 hours (10pm-6am), because your out-of-hours calculation has to account for weekends and possibly holidays etc. Hence it can get quite complex, which is where the solution in my first link might come in.