How do I Loop through a schedule in Crystal Reports - crystal-reports

Question

I'm building a report in Crystal Reports 2008. The report is dealing with employee's schedules. There are time slots where the schedule is open, and time slots where the schedule is unavailable.
Currently, I've built my logic so that it finds the start and end of an unavailable time. The report them tells me how many hours that particular staff person was unavailable.
My issue is that sometimes, staff people have a block at the beginning of their schedule marked as 'unavailable', and a block at the end of the day as 'unavailable', but between the two they are 'open'. Thus, the report says that particular staff person was out the whole day, but they actually worked. It isn't an option to tell these particular staff people how to schedule their day - they decide their own schedule, and I write the report to accomodate their needs.
SCHEDULE_TIME EMP_ID UNAVAILABLE_CODE WORK_LENGTH
7/5/2011 11:00 100 NULL 15
7/5/2011 11:15 100 NULL 15
7/5/2011 11:30 100 NULL 15
7/5/2011 11:45 100 NULL 15
7/5/2011 12:00 100 15 5
7/5/2011 17:00 100 15 5
This example shows how somebody would have a 5 hour block calculated for unavailable time, but it's only 2 appointments. For the code, I'm using DATEDIFF between appointment times.
(Essentially, they have built in more than one 'unavailable' block, and my logic will only accomodate one 'unavailable' block per day).
I'm pretty sure that I need to run a type of DO...WHILE loop within the report in order to calculate the total hours unavailable. I'm just not sure how to structure the loop in Crystal Reports.

Answer 1

Maybe i'm missing something but what you want to do looks straight forward. Two obvious options:
Running total:
Set the field to {TABLE.WORK_LENGTH}
Set the type to sum
Set the evaluation formula to not(isnull({TABLE.UNAVAILABLE_CODE}))
Set the reset on change of group/field {TABLE.EMP_ID} (assuming you're looking for totals per employee)
Formula/sum:
Create a formula field unavailable_time with if not(isnull({TABLE.UNAVAILABLE_CODE})) then {TABLE.WORK_LENGTH} else 0
Create a group on {TABLE.EMP_ID}
Create a sum on your formula field in the group footer