File geodatabases do not support all the features and functions available for personal geodatabases. At ArcGIS 9.2, the most commonly used functions not supported by file geodatabases include DISTINCT, GROUP BY, and ORDER BY, and the set functions AVG, COUNT, MIN, MAX, and SUM are not supported outside subqueries. Support for some of these is likely to be added in future releases.
Because you are selecting columns as a whole, you cannot restrict the SELECT to return only some of the columns in the corresponding table because the SELECT * syntax is hard-coded. For this reason, keywords, such as DISTINCT, ORDER BY, and GROUP BY, cannot be used in a SQL query in ArcGIS except when using subqueries. See SQL reference for query expressions used in ArcGIS for information on subqueries.