The derived column in a pipeline will not be displayed under the partition columns drop down in the Target node.
This issue occurs if the pipeline_interactivity_mode configuration is set to manual in Pipeline advanced configurations and the derived column is not valid or the validation is not done after creating the derived column. Please find the attached screenshot below.
If the pipeline_interactivity_mode is set to manual in pipeline advanced configurations, the derived node has to be validated manually so that this column will be displayed under the partition by drop down in the Target node
To validate you have added derive column successfully, Please click on Validate button on the top right corner of the derive node.
Then click on the Preview Data option in the derive node.
After performing the above steps you would be able to see to the derived column name in 'primary partition columns' drop down in the target node.