Top 100 Customer who are there in previous Year not in Current Year
Thanks for joining in my post. I am not able to find anything like that in the reference manual which you are talking about. Can you please attach the reference manual which you are referring to or else can you copy paste those details here.
The hole expression is quite simple. I sum(values) and then use rank() function to sort the result from biggest to smallest. Then (if I want top 10) I show only these rows where the rank() <=10. I am able to understand the what sum(sales) and rank() does. But it will be helpful for me if you can explain me with your expression.
aggr function creates lots of confusion for me. I am not able to understand how it works. I also checked that with the reference manual but it is not helping me.
The first version of my formula was not quite good because it worked only with these items, which were in boath years ( if they were and in 2008 and in 2009). But the problem was with new items: the items which appeared only in 2009, and wasn't in 2008. So for this reason i used IsNull() function to test if the item is new.