Conditionally joining 2 QVDs

[#1]

Hi,

I have 2 QVDs. QVD A has payment date and account number- QVD B has transaction date, transaction amount and account number. I would like to join A to B so that I can include the sum of transaction amount from QVD B where the transaction date in QVD is greater than or equal to the payment date in QVD A.

Does anyone know the best way to achieve this. I am at my wits end.

Many thanks

[hic]

There are two ways to do this: One is to join the two tables straight off on account number, then run a second pass through the created table, making the calculations.

The second method is to use Applymap() as a lookup function to fetch a value from table B when you load table A. Also here you will need the account number to find the right value. See more on http://community.qlik.com/blogs/qlikviewdesignblog/2012/09/18/one-favorite-function-applymap

A problem is if there is more than one payment tied to an account. Then you don't know which payment date to use for the comparison...

HIC