Quick Set Analysis Question: Clarification Needed!

[#1]

Hi guys,

I have been working with set analysis and have found something that I am unsure of in its use.

I want to completely disregard some fields when they are selected so that they do not affect results. Therefore I would use eg.

=count({$< a= , b= , c= , d= , e=>} distinct System)

However, I also read that this expression could also be used: count({$< a= {*}, b= {*} , c= {*}, d= {*}, e= {*}>} distinct System)

Using this first method I get different results, results that I did expect, do you know why the results differ?

Thanks in advance for help!

bc

[Oleg_Troyansky]

Hi bc,

I'm guessing you have some null values among your data...

Here is my understanding of the difference:

Syntax "a=" means "remove selection in field a", while syntax "a={*}" means "Select all possible values in field a". The difference (and this is just a guess that you should validate) is in null values - in the first case (no selection), the null values are included, while in the second case (all possible values), the null values won't be included.

You should be able to see the same difference manually if you compare the totals when nothing is selected in a given field, with the totals when you chose "Select Possible" from the right-click menu.

Please check it out and let us know if this is the problem or not.

Oleg

[shumailh]

Thanks Oleg,

VERY CLEAR DEFINITION.

I learn from it.