3 Replies Latest reply on Sep 12, 2018 3:49 PM by Okechukwu Ossai

# Visual Table Tracking Existence

Howdy all!

Title may be a bit confusing but had a request for ideally a simple yes/no table. Yes if the column/row exists, no if not.

In that snippet, if there is ever an Abc then it should say "Yes". If it is blank then it should say "No".

I thought about using [Number of Records] and some form of calculation saying "if >= 1 then Yes, else No".

The issue I have is that those blanks are not nulls but rather never exist at all in the dataset.

Is there a solution by chance? have attached sample workbook.

Thanks!

• ###### 1. Re: Visual Table Tracking Existence

This works with the sample dataset. Try it to see if it works with your actual data.

Hope this helps.

Ossai

• ###### 2. Re: Visual Table Tracking Existence

Yes Ossai!

That worked perfectly

I just want to understand how it works though if possible.

I rarely use lookup functions, let me see if I get this correct.

Without the lookup function the calculation should still prove effective in my head, but it does not. It does not work because a value that does not exist is not the same as saying "the value is null".

So the lookup forces a table calculation. It goes cell by cell and says "this cell exists as a piece of this table, therefore is now a part of the dataset. Because it is now null the ZN makes it '0'. Which now triggers the if statement."

Just want to see if I understood that correctly.

• ###### 3. Re: Visual Table Tracking Existence

Hi Jonathan,

You thought process is very correct. What the formula does is a kind of data padding by adding null values.

ISNULL(), IFNULL() and ZN() only work when there are null values. However, in this case there is no data. So, those functions won't work.

What LOOKUP() does, like you correctly said, is to make Tableau generate a null. Then ZN() or IFNULL() can be applied to those triggered null values.

Jonathan Drummey has written extensively on data densification/padding in his blog.