Richard, is the future documented anywhere? 2011/9/15 Richard Hipp <d...@sqlite.org>: > On Thu, Sep 15, 2011 at 8:08 AM, Igor Tandetnik <itandet...@mvps.org> wrote: > >> Richard Hipp <d...@sqlite.org> wrote: >> > On Wed, Sep 14, 2011 at 9:03 PM, Sam Carleton < >> scarle...@miltonstreet.com>wrote: >> > >> >> Forgive me, fore I have forgotten the term used to describe the behavior >> if >> >> a C if statement where it stops executing on the first false statement, >> >> but... Does coalesce do that? >> >> >> > >> > "Short-circuit evaluation" is the usual term applied to this kind of >> thing, >> > and yes, COALESCE() does short-circuit evaluation. If you say >> > "coalesce(A,B)" and A is not NULL than B is never evaluated, which can be >> a >> > significant performance win if, for example, B is a complex subquery. >> >> When did this start, with what SQLite version? > > > 3.6.21 - December 2009 > > >> I must admit I'm somewhat behind (using 3.6.X for some X I don't recall at >> the moment), but in the version I use, in expression coalesce(someField, >> customFunction()) I definitely see customFunction() called even when >> someField is not null. >> -- >> Igor Tandetnik >> >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@sqlite.org >> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users >> > > > > -- > D. Richard Hipp > d...@sqlite.org > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users >
-- Best regards, Alexey Pechnikov. http://pechnikov.tel/ _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
