Shane Dev wrote: > Apart from visual inspection and testing, is there anyway to be sure your > query selects the same results as my query?
Can I interest you in things like relational algebra or tuple calculus? ;-) >>> select * from nodes where not exists (select * from edges where >>> child=nodes.id); >> select * from nodes where id not in (select child from edges); > > From https://sqlite.org/queryplanner.html "When programming in SQL you tell > the system what you want to compute, not how to compute it". Is this an > exception to the rule where the query planner must be told how to compute > the result? Arguable, the second query is on a higher abstraction level, i.e., the _first_ one tells the system how to compute it. (AFAIK SQLite is able to transform an IN lookup into a correlated subquery, if worthwhile, but not in the opposite direction.) Regards, Clemens _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
