Thanks, will try that. Yes, the ID field is an integer primary key autoincrement. Still running the old sql with concatenation. Looks I may need to kill that.
RBS On Tue, Oct 16, 2012 at 11:38 PM, Igor Tandetnik <itandet...@mvps.org> wrote: > On 10/16/2012 6:29 PM, Bart Smissaert wrote: >> >> Actually, it really is slow, made worse by the fact that there is not >> one grouping >> field (value in my example), but three. I am running your SQL now, >> concatenating >> these 3 fields, but still running and looks will be a long time. >> Will have to improve it with indexes and maybe avoiding the concatenation. > > > This would avoid concatenation: > > > update MyTable set Group_Marker = ( > select count(*) from MyTable t1 > where t1.ID <= MyTable.ID and not ( > select (t2.Value1=t1.Value1 and t2.Value2=t1.Value2 and > t2.Value3=t1.Value3) > > from MyTable t2 where t2.ID < t1.ID > order by t2.ID desc limit 1 > ) > ); > > The only index that would be helful is one on ID, which I suspect you might > already have. > > -- > Igor Tandetnik > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
