Blank vs. Null

[jillian]

What is the difference between a blank and a null record?

[Kenda · Accepted solution]

@jillian Blank could mean that it is either an empty string or a null. Null is just null.

[Jes_Li]

Hi Pulsar,

Shouldn't Null mean it's unknown? The value of Null may be missing, empty or could be anything. But blank only mean empty string.

Like someone's middle name is empty just means he/she doesn't have a name, if middle name is Null, then it means the middle name is missing, could be empty, or "A" or "ABC" or anything....

[ChrisTX]

On the page that lists all Functions, click the third icon for Expand All, then look at the examples for the IsEmpty function.

https://help.alteryx.com/current/Reference/Functions.htm

[Jes_Li]

Hi Chris, 

Thanks for the reply. Why do we need to cleanse Null into Blank for string, if Null is part of blank?

[Jes_Li]

Also, I'm confused with definition of Null: 

NULL    

The value for that row is either missing, unknown, not yet know or inapplicable. Null is not zero, because zero is a value. Null is diferent than empty.

https://help.alteryx.com/2019.3/Search.htm?q=null

So if the scope of blank = empty + null, does that mean blank = empty + missing + unknow + notyetknow...   then what's the point of replacing Null with Blank in Cleansing tool? 

Thanks.

[ChrisTX]

Take a look at this video, 5 minutes:

Using Null & Empty in Expressions

https://community.alteryx.com/t5/Interactive-Lessons/Using-Null-amp-Empty-in-Expressions/ta-p/98944

Null versus empty is a long discussion, not unique to Alteryx.  Microsoft Access programmers also have the same questions. 

A Google search should help with examples.

[EricMartinson]

This was very helpful. Thank you!