Set analysis best practice

[#1]

What exactly is the difference between using the - sign as a set operator in a set analysis and using -= as a set identifier.

For example, what is the difference between these two expressions?

COUNT(DISTINCT {$<TestAccount={'false'},UserName-={'*test*'},Firm-={'*TEST*'}>}SessionId)

and

COUNT(DISTINCT {$<TestAccount={'false'}>-<UserName={'*test*'},Firm={'*TEST*'}>}SessionId)

Please don't copy and paste help text from the application as it is not hugely helpful. If anyone could explain it in plain english, that would be be great!

thanks very much

Alex

[anbu1984]

UserName-={'*test*'}  - Select Count(Distinct SessionId) from table where TestAccount='false' and UserName Not Like '*test*'

TestAccount={'false'}>-<UserName={'*test*'}

Select Count(Distinct SessionId) from (

Select SessionId from table where TestAccount='false'

Minus

Select SessionId from table where UserName like '*test*' )

[#3]

Both expressions will count distinct sessionIDs with TestAccount = False,

The first will exclude Usernames like TEST and Firm like TEST.

The second expression in also counting distinct TestAccounts that are false, but will include Username like Test and Frim like TEST. 

[#4]

Hi Alex,

I would take a look at this thread maybe, will give you a good overview of what the signage is doing

http://community.qlik.com/docs/DOC-4951

hope that helps

Joe

[ashfaq_haseeb]

Hi,

Check this.

Romancing with Set Analysis

regards

ASHFAQ

[jerem1234 · Accepted solution]

Hi Alex,

    You have to be careful interchanging the two. I have attached a difference in your example depending on the kind of data you might have. The counts can be different. Here is an image explaining what happens (also attached the qvw):

Hope this helps!

[#7]

Thanks Jeremiah. That was very clearly explained. Exactly what i was looking for!

I had overlooked the fact that the expression below meant AND and not OR

<UserName={'*test*'},Firm={'*TEST*'}>