SELECT tool

[Sreedhar_2798]

Can someone give the detailing on why we need to always make sure that we are selecting the "Unknown" column while using "select" tool? A brief explanation around this would be really helpful

[JosephSerpis]

Hi @Sreedhar_2798 the help documentation of the Select tool says "The Unknown column is selected by default. It allows new columns in the data. Move the column to the location where you want a new column to be." 

[PanPP]

Hi @Sreedhar_2798 

The *Unknown represents any fields that may come into the tool which it did not know about when the module was originally built. If it’s selected then any new fields from the data stream will continue downstream for further processing and perhaps be included in outputs, if deselected then any new fields will be dropped. Generally, you probably pay little attention to this and generally, it won’t really affect your processing, but there are occasions when it can be quite useful.

Please take a look at this article for more details - https://community.alteryx.com/t5/Engine-Works/Dynamic-Unknown-Fields/ba-p/2041

[grazitti_sapna]

@Sreedhar_2798 , it is explained in the documentation of Alteryx. Whenever you face any issues like these you can go through the documentation to get any clarification on any tools. Here is the link to documentation:

https://help.alteryx.com/20223/designer/select-tool#:~:text=Use%20Select%20to%20include%2C%20exclude....

[ShankerV]

Hi @Sreedhar_2798 

The "Unknown" column will be selected i.e., check box will be selected by default.

It helps to include the columns in future if more columns are added in the Input in future.

Example 1:

Input file contains 3 columns

In the Select tool, the Unknown (Which is dynamic) is unselected.

After Ctrl + R (Run) then the result is 

Example 2:

Next time the Input file contains 5 columns where 2 columns are added.

In the Select tool, the Unknown (Which is dynamic) is unselected. Hence the Select tool is not dynamic to include the new Columns added.

Hence the result will be only 3 columns.

After Ctrl + R (Run) then the result is 

If the Dynamic (Unknown) is selected, then the column D and E will be automatically selected.

If you believe your question has been answered. Please mark helpful answers as a solution so that future users with the same problem can find them more easily!!!!

Many thanks

Shanker V

[Alteryx_AR]

@Sreedhar_2798  Good question ! If your input file is updated and new columns are added to the table, then the new columns will automatically be selected if you leave the box checked. If you uncheck the box, then it will not select any new columns.