Unknown Field in Select Tool

[CMorg16]

What is the purpose of the Unknown Field? How would this impact my workflow if I leave it checked/unchecked?  

[Armon24 · Accepted solution]

The Dynamic/Unknown field (column) shows up and is checked by default in the configuration properties of the Select tool (as well as other tools).

The purpose of this field is to allow new fields to come in, in cases where your input file might change. It gives you the ability to determine where new fields go in the file by moving the field's position.

https://help.alteryx.com/20223/designer/troubleshooting-and-faq 

[ThomasT]

Hi there,

If you leave it checked and 'New Fields' come in through your data flow the select tool will let the 'New Fields' flow through. 

If you de-select the 'Unknown Fields' it will not allow 'New Fields' to flow through the select tool and only stream out those fields which were previously checked. 

Similar principle across multiple tools within Alteryx eg Cross-Tab/Transpose.

[PanPP]

Hi @CMorg16 

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.

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