> Is Relations_Index1 not the most efficient one? It might be. We need the rest of the schema to know. To use Relations_Index1 efficiently requires a key value for IDSecondDatum. Which means moving table Relations to the innermost join of the QUERY PLAN. Which means we can't use the extremely efficient rowid index for table Classifications. What's the alternative to that? Are there indexes on Classifications.System or Classifications.GameType? Dan.