You have them quoted, so what's the problem? Perhaps TIMESTAMP only goes to milliseconds--try omitting the last 3 zeros and see if it takes it.

I'm a bit confused the way you reference column filefield in your example. Is it meant to imply that filefield is defined as a timestamp, or that the values of filefield should be interpreted as timestamp values, or is it something else I've failed to consider? It's not typical notation for DB2i. If the column is defined as a timestamp, no qualifier would be needed (What does .timz represent?), SQL will convert to constants to timestamp for comparison. If the column is defined as a numeric, or a character, you'd format the string and convert it to a timestamp value using the timestamp function, and your SELECT statement would look like this: SELECT * FROM filename WHERE TIMESTAMP( formatted_filefield ) BETWEEN ts_value1 AND ts_value2 FWIW, DB2i translates its internal representations of dates, times and timestamps into external values that are locale friendly based on format settings.