Derived fields - $1 meaning & AutoCalendar

[piotr-bratek]

Hi Guys,

two questions:

1. Can you pls give me any other real-life, valuable example of using DERIVE & DECLARE instructions than AutoCalendar scenario?

2. I'm testing DERIVED and DECLARE instructions, reading Help but can't really get the idea of this 'referenced field'. Help says:

Use $1 to reference the data field from which the derived fields should be generated.

Example:  

Year($1) As Year tagged '$year'

I've tested a typical scenario with AutoCalendar and 4 dates:

DERIVE FIELDS FROM FIELDS [OrderDate], [Date], [RequiredDate], [DeliveryDate] USING [autoCalendar] ;

Is there any reason to change $1 to $2? Is there any other case which works and makes sense?

Scenario 1 - using $1

Scenario 2 - using $2

Many Thanks!

[rwunderlich]

$1 is simply a placeholder for the field being processed.  In your posted example, all fields tagged with '$date' will get processed. If the current field is 'OrderDate', the $1 gets substituted in the script and you have:

Year(OrderDate) As Year tagged '$year'

No, it does not make sense in this example to ever use $2.

-Rob
http://masterssummit.com
http://qlikviewcookbook.com
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[piotr-bratek]

Thanks Rob! That makes it clear. What about Question 1? I know I could find some potential scenarios, but out of curiosity 🙂 - have you ever applied this method to create some derived dimensions other than dates ?