Greetings!
I created a joiner in KNIME and it duplicated several rows. How can I solve this?
As I stated in the prints below, I only need the information from the first and last rows, I don’t need the middle ones. Of course, I’m filtering a specific ID from my table.
Joining explodes the rows whenever there is a many-to-many relationship, where one row from each side could potentially map to several rows. You could solve it by removing the duplicates from the “lookup” table or e.g insert more than one join criterion to make the matching more explicit (depending on the use case)
Could you please share the config window of the joiner node?
Could you please share the workflow & the data sample for both tables & desired output?
Hi @rodolphovieira , it would be nice to include the data in the workflow example to demonstrate and test. We cannot read anything from your local files. 
You can simplify and complete the workflow by removing irrelevant nodes and add Table Creator nodes to generate sample data.
In the first screenshot, the green highlighted “ID_Material” is identical but the “TAG” is different. Already this single difference leads to “duplicate” row - just because they are not real duplicates in terms of the complete row.
If you really need this data, think about adding a GroupBy node after the joiner and create SETs from the strings causing the duplicates. Otherwise use a column filter upfront or just sort out the problem columns in the joiner.
Use also the “Duplicate row filter” node for checks of duplicates (config: Keep duplicates), followed by a row filter which sorts outs the “unique” ones.
