Another Date Set Analysis question

[#1]

I'm trying to do something apparently very simple which is a value from a previous month, but I just can't get it. I've tried with:

sum({1<Date={'$(=Addmonths(Date,-1))'}>} Amount)

but it doesn't work. Can anyone point out what's wrong?

[#2]

I think your Set Analsysis is requiring the Date to be one month less than itself. I think that will always be the empty set.

I used this (with a variable in the AddMonths) and it worked:

Sum({<Date = {'$(=AddMonths('$(=vDate)', -1))'}>}Amount)

Remember, you can see what you dollar sign expansion evaluates to be placing the expression in a straight table and not using a label. If you expand out that column, you will see your Set Analysis expression with the dollar sign expansion evaluated.

[#3]

Thanks for your answer.

That would help me if the comparison date was always static, but basically what I'm attempting to do is have a pivot table with the Monthname(Date) as a dimension, and as expression the sum of Amount from the previous month. I hope that made sense

[#4]

I forgot to add, I've tried using below, but it's not working either..