Create Computed Column using data from another table

Question

I have a SQL Server 2008 R2 database. This database has two tables called Pictures and PictureUse.

Picture table has the following columns:

Id (int)          


        

Answer 1

you dont have to add the computed column to your table, because, after its updated,if the original table data got changed, then data become inconsistent , you can always use this select statement to get the column count, or create it as a view

select p.id,count(*) as count 
from Picture P
join PictureUse  U
on p.id=u.Pictureid 
group by p.id