How to make a many-to-one join?

KNIME Analytics Platform
1

Hello everybody.I’m a fresh man here!

I’ve just started using KNIME to perform Data Mining.
During my work,I often join two or more tables by many-to-one join.
Perhaps I have not learnt well and also my poor English,but it seems to me that KNIME can only support one-to-one join.
So now I’m wondering if it is possible to make a many-to-one join using the Joiner node.

For example,here are two tables,
the table A is:

column1,column2
1,2
1,3

and the table B is:

column1,column2
1,4

after joining on A.column1=b.column1,I want the result be as below:

A.column1,A.column2,B.column1,B.column2
1,2,1,4
1,3,1,4

Can anyone tell me if it is possible,and show me how to do this?

Thanks a lot in advance for your answer !

Herro

2

Hi Herro, I guess this forum topic might be interesting for you. This is a sample workflow. (I guess this was my best explanation there.) Bests, gabor

3

Hi,

The Knime joiner node uses the RowId of the first (top) input and allows the second table to be joined on a column value from that second table. You can use the RowId to use a field (as long as it is a unique indentifier) as the RowId value.

So if the first (top) input is your “one” and your second input (bottom) is your “many” this should work fine.

I hope that helpds.

Jay

4

to friends above:
My many-to-one join is work.It’s simple,and it seems what I thought is far too complex~
Thanks very much!
Herro

5