I do not have much experience with SQL
I come here to lend a helping hand to those who want to improve their experience.
I came to this site because I was searching for help with SQL queries/coding
So if you really are looking for guidance to help you solve the problem and not a ready made solution done for you......then
There is no "magic" way to do this. At least ... there isn't in SQL Server 2000 that I am aware of.
You will have to perform math in your query to calculate it
getdate returns the current date
weekday returns the day of the week for a date. 0=Sun,1=Mon .... etc
using those to functions as well as the NumDaysIncidentOpen in your query you can use math to get a precise NumWorkDaysIncidentOpen in the query.
It can get a bit hairy if you have partial weekends but since you call it "Number Of Workdays" I assume you won't have any.
Something like this
Find out how many workdays for the current week to today
Subtract that from NumDaysIncidentOpen
If remainder is positive then divide the remainder of days by 7 to get the number of weekends
Subtract NumWeekends * 2 from NumDaysIncidentOpen to get the Number of workdays.