Database Concatenate node


Is it possibile to concatenate two database branches into one? It seems that knime misses a Database Concatenate node (in the Database/Manipulation familiy).

Thanks in advance


1 Like

You mean a UNION of two tables?

Hi Thor, Yes, I mean a Union.


there is no native node availabe but please see the workflow attached. There are two wrapped nodes you can use to apply different set operations. Use UNION for the concatenate option.

We will release such a node in the near future as well.

Best regards, 


1 Like

Hi Iris,

thank you very much! Impressive! I think it's an excellent solution in the mean time...


Hi Iris,

are there any news concerning the Database Union / Concatenate node?

Kind regards,

Hi Agaunt,
no sorry, this will not make it in the next release. I will give it a +1 from you.
Cheers, Iris

Yes, Union would be great, and even more advanced row filtering (e.g. Nominal)


I would like to see this too please

Hi there,

all your requests have been noted.


Hi @Iris I was using your fantastic node :slight_smile: Everything was great when I used s4/hana databeses. However, when I connected to mySQL database it didn’t work. It only took data from the first node (UNION) or double data from the first node (UNION ALL). Both tables which I want to combine/union, has the same stucture. Is it possible?

Give another +1 that it will be in next release :wink:

Ps. When I use concatenate node - everything is ok, but I want to do this in database

Hi @Tom

I have to admit all credits for the nodes go to @tobias.koetter I just did some beautifications.

That sounds strange. I just checked and MySql does not have a special union syntax, it seems standard. Did you try this on a very small example table? Just combinng a few rows and both tables have one column only?

Best, Iris

I tried - please find attached

Best, Tomek

Hello Tomek,
what command do you use in the SQL Set Operator node? Have a look at the SQL that is generated in the node by opening the out port view of the SQL Set Operator component. It should look similar to this one

e.g. two select statements combined using the UNION command.

1 Like

Hello Tobias, I attached SQL view, it very simple

second one is the same, only difference is UNION => UNION ALL.

Below a attached SQL view, where I connected to data base S4/Hana, and it’s work.

Best, Tomek

I think I found sth. When I changed enter ports, SQL statement only takes data from the second database, its another IP, port and database name.

so it’s seems to work, only when I UNION tables form the same database?

1 Like

Hi Tomek,
that explains it. The node only works when you concatenate data within the same database. the database doesn’t know how to load data from a completely other database. In your case it didn’t throw an exception since the second table name also existed in the first database and it simply concatenated the same table with itself.


Hi there, 4 years later and still no Union Tool???


And this “SQL Set Operator” works only with “legacy” nodes, not with the new one :frowning:

Hi KNIME, any update to this problem?