Den 13.02.2017 20:40, skrev Dimitry Sibiryakov s...@ibphoenix.com [firebird-support]: > Hello, All. > > If I use prepared statement like this "update table set field1=?, > field2=? where > field3=?" for performance reasons, is there a way to update only some fields > and leave > other untouched without overhead of building separate queries on the fly or > selecting old > values with different query?
I'm more of a SELECT than UPDATE guy (and haven't tried my suggestion), but wouldn't update table set field1=coalesce(?, field1), field2=coalesce(?, field2) where field3=? get the right result (well, unless you could have instructions like "Set field2 to <null>;")? Theoretically, I would of course expect such a statement to "change" the value to the existing value rather than leaving it untouched when the parameter is <null>. HTH, Set ------------------------------------ ------------------------------------ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Visit http://www.firebirdsql.org and click the Documentation item on the main (top) menu. Try FAQ and other links from the left-side menu there. Also search the knowledgebases at http://www.ibphoenix.com/resources/documents/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ------------------------------------ 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: https://info.yahoo.com/legal/us/yahoo/utos/terms/
