Create calculated column of two tables inside script

[#1]

Hello community,

This question is related to my previous post:

http://community.qlik.com/message/322989#322989

I have two tables with the following (simplified) structure:

DataTable:

LOAD

...

Amount,

InvoiceCurrency,

if(NOT Wildmatch(InvoiceCurrency,'EUR'), InvoiceCurrency&'-'&CutoffDate,'EUR')  AS ComboCurrDate

...

EcbTable:

LOAD

ComboCurrDate,

ECBrate

So the tables are linked through the ComboCurrDate column.

I want to add a column for EurAmount so that I can use this field in set analysis and other scenarios.

Right now I use this statement to calculate the EurAmount outside my script:

if(NOT Wildmatch(InvoiceCurrency,'EUR'), (Amount / (1 * ECBrate)),Amount)

What do I need to do to create this calculated column? Create a third table, use a join - do I need a real key field?

I hope you can help me out here.

thank you.

[#2]

DataTable:

LOAD

...

Amount,

InvoiceCurrency,

if(NOT Wildmatch(InvoiceCurrency,'EUR'), InvoiceCurrency&'-'&CutoffDate,'EUR')  AS ComboCurrDate,

'  ' as EurAmount

...

EcbTable:

LOAD

ComboCurrDate,

ECBrate

[#3]

I don't get it

This way I still have to use the if statement in every expression, don't I?