Find when the last time you received an order from a list of vendors in Crystal Reports or SQL

Our company has thousands of different vendors in its ERP system.  Many of them we no longer use.  I'm trying to figure out the best way for me to create a report that will show me a distinct list of suppliers that we have used.  Or a way to show the last time something was purchased or received from a vendor.  I can use SQL, Crystal Reports or Excel to create this but would need the thought process of what to filter the report on.   My goal is to review vendors where we have not had usage from say the past three years and eliminate them from our database.