--- [EMAIL PROTECTED] wrote: > "Robert Simpson" <[EMAIL PROTECTED]> wrote: > > > > By leaving it undocumented and not committing to today's implementation, DRH > > leaves himself open to change or optimize it later without breaking backward > > compatibility. > > > > Exactly. > > Furthermore, if you put on an ORDER BY clause that would result > in the same ordering as would come out of the query naturally > (that is to say if the result without the ORDER BY would have > been the same as the result with the ORDER BY) then SQLite will > automatically optimize out the ORDER BY clause so there is no > performance penalty for using it. So put in the ORDER BY. It > will cost you nothing in performance today but might save you > from embarrassing bugs in your application if future enhancements > to SQLite cause the natural order to be a little different.
Oracle surprised a few programmers when they changed their implementation of GROUP BY to not return the results in GROUP BY sorted order. They may have changed their GROUP BY to use a hash-based algorithm rather than basing it on a sort. In any event, such implicit ORDER BY sorting when only using a GROUP BY was never guaranteed by the SQL standard. If you intend the results to be sorted, you must use ORDER BY. ____________________________________________________________________________________ Don't get soaked. Take a quick peak at the forecast with the Yahoo! Search weather shortcut. http://tools.search.yahoo.com/shortcuts/#loc_weather ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
