Conditional VLookup for null Values

[DrExcel]

Hello ALTERYX community, 

I have a monthly mobility device information report.  Some (5 records this month) of the values (Activation Date, Model, Manufacturer, IMEI, SIM) are null in the current file as the lines are no longer on the account - but I would like to preserve this information.

Pre-Alteryx, I would have simply done a VLOOKUP from the historical (last month's) file for these 5 records.  

The current month's file has Wireless Number, Rate Plan Information, etc.. it is simply missing the device details.

I assume I have to do a join - but when poking around through the tool it seems that this tool is intended to bring entire columns of data over based on a join criteria (Wireless Number in this case) as opposed to bringing over only the missing information.  

I realize that I could bring over these 5 columns for ALL the records, but several of the lines certainly have been upgraded during the last bill cycle... and by doing so, I would be overwriting the current information

Really been enjoying learning all about Alteryx these last couple days and looking forward to automating all of my data sanitizing via these wonderful tool before loading it into my downstream databases.  

[cplewis90 · Accepted solution]

Hello @DrExcel!

Welcome to the awesome world of Alteryx! One thing you could do is before the join filter down to the records needing to fill the data and then unioning what joins back with the records that didn't need any updates.

[DrExcel]

So - between when I posted this and now - I have spoken to my colleague who schooled me on a way to accomplish the above.

EDIT: It also seems that @cplewis90 answered in a similar fashion before I saw it!

Step 1 - use the filter tool to split based on criteria (empty/not empty in this case)

Step 2 - Join the Empty results to the historical data (I made sure to remove the rename fields for the right table as in my case the fields were identical)

Step 3 - union the Not Empty Results to the Empty results and voila!

Thanks to my main man Georgie Tables who is always the man with the plan!

Hope this helps someone else in the future! 

Have a great day folks!