Conditional Execution of knime nodes, specifically excel appender not working under specific circumstances

Hi All,


I am having a workflow that analyzes multiple datasets and writes respective reports into a dedicated Tab of an Excel sheet (using Excel Sheet Appender node).

However sometimes certain excel tabs will not contain data, so the resulting excel sheet might contain many empty tabs.

In order to avoid that I would like to only execute the respective Appender node in case data is passed to it, otherwise skip the node. 

I have not found a solution yet.

Any idea?





Hi Matthias,

you can use an "IF Switch" or (fitting your use case quite precisely) an "Empty Table Switch" to achieve this.

Hi Johannes,

yes I am aware of these nodes, unfortunatly in my case it does not work as needed. When trying the "IF Switch" and a node does not deliver data than indeed the following "appender" node will not be executed. However this in turn means that all following appender nodes do not get executed as well. See my screenshot please. All appender nodes are being linked by the variable ports, in order to make sure they are all executed (and in the right sequence). Once any one of them get's not executed all the following "appender" nodes will not be executed as well.