Feature reader where clause across 2 tables

I do not know a way to do this at the moment. I think you want to create an Idea and / or a support case for this.

Hi ​@tmatiques,

Thanks for the great question! This isn't possible within the FeatureReader because per-feature type filter mapping doesn't currently exist. FeatureReader only provides a single reader-level WHERE clause and that same clause applies to every selected layer (feature type) so it can't apply a filter to only one of the selected layers while leaving others unfiltered. I agree this may not be very useful in a lot of cases.

For your scenario, I would either add another FeatureReader or a standalone ArcGIS Feature Service Reader (exposes a feature type-level WHERE clause within each individual feature type) to query that single layer. 

If you'd like per-feature type filtering at the reader-level when multiple layers are selected for Feature Services (eg. inside a single FeatureReader or Feature Service Reader), I would recommend you submit an FME Idea and outlining your intended use cases. Perhaps the layerDefs parameter from the REST API documentation may be relevant here? This will allow other users to upvote, raise awareness to our developers, and help us gauge interest for potential future support. Hopefully this clarifies the limitations and available options.

Does your request differ from this idea?

Enable Different WHERE Clause for Different Feature Types within the FeatureRade | Community

This was merged into this idea

Enhanchment of FeatureReader | Community