I am running into an issue currently with a model I am trying to build that will automate isolation of polygons into new feature classes that have two fields with values not equal to each other. The first run worked fine on the test dataset. However after trying on another, I recieved the 000358 Invalid Expression error message while running the select(analysis) tool. Upon researching the attribute tables, I discovered that the same field was named PLOT_MASTER_LEADING_SP in the first feature class, and the other was PLOT_MASTER_LEAD_SPEC_ in the second feature class. This difference is due to the required input of field names being different during each of their respective years. So my question would be, is there any way to build a selection query in the model that will not give me an error and includes both possible field names? I have tried "OLEADSPC" <> "PLOT_MASTER_LEADING_SP" OR "OLEADSPC" <> "PLOT_MASTER_LEAD_SPEC_", but still get an error message as it needs to retrieve both fields for this query.