InformedJoin - how to pass flow variable for joined columns in join

Hi all,

First of all, I am quite new to KNIME. Having visited the KNIME Spring Summit in the past week I can nog officially call myself a KNIME enthousiast.

I created a wrapped metanode to provide me with more information about a join (and mismatches) in the fourth output port:

InformedJoin InformedJoin_info

The first three output ports are the left join, inner join and right join.

I find this useful, but want to apply a finishing touch to make it more convenient to reuse in other workflows. As of now I have to pick the columns to be joined three times (for the left, inner and right join sperately):

I searched for a flow variable that I can use and pass to the latter two after configuring only the first - if possible it would be even better if this could be configured without entering (ctrl+double click) the wrapped metanode. I found “getLeftJoinColumns()” but cannot find this in the flow variables tab.

Any ideas on how to solve this?


I think what you would have to do is prepare as many ‘dummy’ Join entries as you would like to have in advance. If you have fewer you might try to set one ID twice (should not affect the outcome).

kn_example_joiner_variables_flow.knwf (22.7 KB)


It works perfectly, thanks a lot!