I'm not to sure what the best way to go about this is, so i'll describe what the end goal is, and if a computed column is the answer then please help me go that route, or perhaps a better route.
I have two tables:
Orders
OrderId
PackageId
MediaSpend
TotalAdViews (Computed column)
Packages
PackageId
BaseAdViews
Each order is assigned a package that comes with say 1,000 views, you can then buy more media spend to get more views. I wanted to create a column called TotalAdViews which would add BaseAdViews + MediaSpend. From my understanding if persistance is enabled the column won't need to recalculate every time it is queried, which could help performance.
How do I get a value from another table in my computed column? Or please suggest an alternate way of accomplishing my goal.
Best Answer
I know this answer comes two years late, but just to help anyone who googles and finds this post:
It is perfectly legal to define a user-defined function and use it as the computed value. This function may contain select statements from other tables.
Then in your computed column, just use the expression
dbo.getSumAdViews(PackageId)+MediaSpend
as so: