I have this simple select select sum(apos.f_gewicht) as Gewicht from t_apos apos where COALESCE(apos.f_dat_anlieferung, apos.f_dat_erstellung) between '2013-01-15' and '2013-01-16' which does an natural scan on table t_apos although an index is on both fields.
select sum(apos.f_gewicht) as Gewicht from t_apos apos where apos.f_dat_anlieferung between '2013-01-15' and '2013-01-16' and select sum(apos.f_gewicht) as Gewicht from t_apos apos where apos.f_dat_erstellung between '2013-01-15' and '2013-01-16' both uses the index . Why is the index not used when coalesce is used? I use Firebird 2.5.2 64bit on Windows 7. Carsten ------------------------------------ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Visit http://www.firebirdsql.org and click the Resources item on the main (top) menu. Try Knowledgebase and FAQ links ! Also search the knowledgebases at http://www.ibphoenix.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/firebird-support/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/firebird-support/join (Yahoo! ID required) <*> To change settings via email: firebird-support-dig...@yahoogroups.com firebird-support-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: firebird-support-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/