Column: no fields were selected for a column

[jdkatz1]

Hello, 

I keep getting this same error. Not really understanding where its coming from as all the columns are aligned from the two data sets

[ShankerV]

 Hi @jdkatz1 

The problem is here.

Col77 is not assigned with no fields. We cant keep it blank.

[jdkatz1]

I have 4 blank columns. There is no additional data to fill these. Is there a way to remove it so it will work? or another way to fix?

[apathetichell]

my recommendation would be hooking up a dynamic rename in formula mode to the stream with the "Right_" prefix and then union on name. In your dynamic rename use the formula:

replace([_CurrentField_],"Right_","")

Your current issue is that you are manually configuring fields in a union tool. Using this config is great but in situations where schema changes (or there are lots of columns) it can create errors...

[jdkatz1]

why is it creating all of these columns though? shouldn't there be a way to prevent this from happening while still being able to do it manually configured?

[apathetichell]

There is - if you select "Deselect dupes" on your join you won't carry forward the second instance of the named column. By default duplicated column names on the RIGHT are relabeled as "Right_" post join. This is because you cannot have two column names which are the same and SQL is left/top dominant.

and just to go back to my initial statement - manual configuration on imperfect schemas will create errors. stick with configure by name - and get your names to match prior to the union.