how to use aggregation functions

[#1]

Hi,

I am developing a view for hospital maintenance.

In that we schedule cases to be perfoemed in future dates.

sample data  i loaded into qvw file.

and i want to find out,

what is the prevous case delay in particular room and add that dealy to next scheduled case in that room and show...

I did this using script.

but doing so i need to 3 resident loads which may cause some perfomance issues.

so i wanted to do these caluculations in table  itself.

please any suggestions and help ......

it's urget for me.

Thanks to all..