Set Analysis - Qlikview 11 for developers

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Obtaining the base period record set A simple  Max(Period) expression will help us get the base period in all scenarios,

as the  Period field contains both the  Month and  Year components. Therefore, the set modifiers that we would use to get the record
set corresponding to the base period in each of the required comparisons are:

•  Current Year-To-Date indicators:

<Period = {"<=$(=Max(Period))"}, Year = {"$(=Max(Year))"}, Quarter

= , Month = >

This set modifier will result in a record set containing all of the periods that are less than or equal to the current period, and belong to
the current year, which would be all Year-To-Date records.

Question -

If the "Period field contains both the  Month and  Year components", then why do we use Period and Year in our Set expression ? Why not use "Year and Month" instead ?

[tresesco]

This is all about how you want the users use filters. If you want to use Period field in the set, you can. Then you have to take care of the selection interface( if you allow or not to select from Year field, if yes, then you have to bypass it in the set expression). Use the book examples to understand the concept; it's not that always you have to follow exactly the same way. Once you get to know some betterment ways, you would be able to implement it in your application in your own way.