Null Values After Join then Union

[LDP616]

Hi,

Having an issue after a join then a union. After the join there are records that fall out an records that join with data i require. I am unioning back in data that I know will have partial null fields (which I will then cleanse to denote). The union works, creating the amount of rows I am expecting, but all the data that was previously populated is now null. 

Any ideas on why I am having this issue would be useful!

-All fields are ticked in the join and are passing through

-I have attached a screengrab of the configuration of both tools

Thanks,

LDP616

[TrevorS]

Hello @LDP616 

Thanks for posting to the Community!
Are you able to include your workflow and some sample data so that we can see what's going on?

Thanks!
TrevorS

[pedrodrfaria]

Hi @LDP616 

It will be a lot easier if you could share the workflow.

If I understood it correctly, when you are adding the union afterwards you need to pay attention because then you will have duplicate columns and then many rows/columns being null. My recommendation, prior to the union, add a select and properly name all the columns so you do not have an instance where a column is renamed by Alteryx due to being the same name as other (ex: Right_Column1) and unselect any possible duplicate columns. After doing this with the select tools, you can union everything by name and should have a clean dataset.

This happens because The L output and the J output will have the same columns, with the J output also having some columns from the R output, this is why they get duplicated and we would need to do this.

Pedro.

[LDP616]

Thanks guys, appreciate it!

Module attached!

[AndrewS · Accepted solution]

Hi @LDP616 

I think you need to remove the NULL values and then change the join fields - I've attached a reconfigured workflow - you will need to drop the files onto it as it's not packaged.

[LDP616]

Thank you so much! this has been driving me insane. 

Do you know why wouldn't the Null's just drop out on the left side?

Appreciate the help,

Lauren

[AndrewS]

Hi Lauen,

I think the issue on your original workflow was you were joining Code to CodeName and you were only getting the join on the NULL values.

We have changed the join criteria to Code / Code. There are no nulls on the Code field on the right side (nulls only on the Code Name). You could drop the Null filter on the Left side and have them return on the unjoined L side. Keeping the filter will give you a clearer view of the unjoined values which contain data  - in this case where Code = GA N.

Cheers,

Andrew

[LDP616]

Great, thanks again for your help, much appreciated!

Happy Alteryxing! 

[AndrewS]

Not a problem.

[Madsss]

Hi All,

I am facing the similar issue where my data in the SELECT tool is coming properly but when I combine it to the Union tool with other inputs, my values get converted into NULL.

I also checked the names, types etc everything is same to my other inputs getting combined to Union tool. please help