> Subtracting two times fields we get seconds in decimal format.
> This doesn't bother me anymore, if I want to subtract two time fields.
>
> How can I substract 3 fields: time1 - time2 - time3
>
> example:
> 3:00:00 - 1:00:00 - 0:30:00 = 1:30:00 (or 5400 sec)

time1 - time2 -(time3 - cast('0:0' as time))

Ivan