| I have only been able to find examples where geometry attributes are returned from cross layer filtering functions, but the GeoServer documentation says:
A common use case is to extract a geometry-valued attribute, and then use the value(s) in a spatial predicate against a geometry attribute in the primary layer.
Which leads me to believe that it was intended to be used to return other data.
I have attempted something like this: http://localhost:8181/geoserver/test/wms?service=WMS&version=1.1.0&request=GetMap&layers=test:layer1,test:layer2&styles=&bbox=-81.54053,41.61621,-77.33826,43.41248&width=768&height=330&srs=EPSG:4326&format=application/openlayers&cql_filter=INCLUDE;property2a=querySingle('test:layer1','property1b','property1a=123') Where only records in layer2 that have layer2.property2a = layer1.property1b are returned. I get the exception: "Could not parse CQL filter list." Similarly: http://localhost:8181/geoserver/test/wms?service=WMS&version=1.1.0&request=GetMap&layers=test:layer1,test:layer2&styles=&bbox=-81.54053,41.61621,-77.33826,43.41248&width=768&height=330&srs=EPSG:4326&format=application/openlayers&cql_filter=INCLUDE;property2a IN queryCollection('test:layer1','property1b','INCLUDE') Where the values of layer2 will only be returned if layer2.property2a has a value in the returned values from layer1.property1b |
