How to concatenate information in different rows

Hey guys!

I need some help, I didn’t find anything talking about how to concatenate information in different rows.

My situation is:
I have to check values of 4 columns, being all the same, I need to delete the duplicate row. That’s already done.
The problem is:
in another column I need to concatenate a cell of the row that will be deleted with the row that will remain.

I’m trying to use Column Expressions, but I don’t know how I’m going to concatenate a row cell with the previous row.

In the example table I am trying to demonstrate in a very simple and abstract way the situation of the table.


Thaks for any help!

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Hi @Andre_Oliva & welcome to the KNIME community !

This can be done using the -GroupBy- node with your 4 columns as grouping columns and the 5th column, the one you want to concatenate as the Aggregation column (use concatenation operator with a plus separator). Please select too that you do not want to change the names of the aggregated column. It should do the work :wink:

Hope it helps.



Edit: I forgot to mention that with this solution one doesn’t need to eliminate the duplicated rows beforehand.


Hey @aworker

I thought it would only work by selecting only the columns that contain the duplicate values.
But I had the same result selecting all the columns except the one I performed the concatenation.

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