MariaDB 触发器将时差计算为总小时数的小数和小时的十分之一始终向上舍入

Question

I have a table that contains these columns:

start_time datetime
end_time datetime
billable_time decimal(3,1)

The billable_time column is calculated with a trigger on insert and update as the total number of hours and tenth of hour as a decimal; however, I want it to always round up the decimal as opposed to rounding to the nearest digit. When creating the trigger, I cannot figure out how to make it always round up the decimal. This trigger calculates it correctly, but it rounds it down if that is the nearest digit:

SET new.billable_time = CAST(TIME_TO_SEC(TIMEDIFF(new.end_time, new.start_time))/3600 as decimal(3,1))

For example:

start time = 2020-06-01 11:00:00
end_time = 2020-06-01 12:22:08

Results in

billable_time = 1.4

But it should be 1.5 if it always rounds up.

I have tried using the CEIL() and CEILING() functions, but they round it up to the nearest integer, which is 2.

I cannot seem to figure out how to make it do what I want. Is it possible to do this in a trigger? Any help would be greatly appreciated. The database is MariaDB v10.4.13.

Thanks in advance.

Answer 1

A simple solution is to add half of a tenth of second to the value before cast ing it:

SET new.billable_time = CAST(
    TIME_TO_SEC(TIMEDIFF(new.end_time, new.start_time))/3600 + 0.05 
    AS decimal(3,1)
)

You can also use ceil() : the idea is to first divide by 360 instead of 3600 , then round with ceil() , and finally divide by 10 :

SET new.billable_time = 
    CEIL(TIME_TO_SEC(TIMEDIFF(new.end_time, new.start_time))/360) / 10