On Sun, Nov 15, 2009 at 10:39 AM, Tim Romano <tim.rom...@yahoo.com> wrote: > I have a query with joined inline views that runs in about 100ms against > a 4 million row table joined to a 275,000 row table. Not bad, SQLite :-) > > But when I use the LIKE operator instead of the = operator, the order of > the query plan changes, though the same indexes are involved, and the > query takes 40 seconds. I'm trying to figure out what, if anything, I > can do to guide SQLite here. > > In broad terms, what is it about the use of the LIKE operator that > causes SQLite to re-order the plan, and is there any way to guide? >
LIKE doesn't use indexes, although there are tricks that these SQL gurus will probably tell that could help you with workarounds. LIKE does a full scan. > And what does the "from" column in the explain plan results refer to? > Are the values the tables/relations in the query statement? If so, how > are they mapped? In order of appearance in the statement, so that 0 is > the first table mentioned in the statement? > > Thanks > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- Puneet Kishor http://www.punkish.org Carbon Model http://carbonmodel.org Charter Member, Open Source Geospatial Foundation http://www.osgeo.org Science Commons Fellow, http://sciencecommons.org/about/whoweare/kishor Nelson Institute, UW-Madison http://www.nelson.wisc.edu ----------------------------------------------------------------------- Assertions are politics; backing up assertions with evidence is science ======================================================================= Sent from Madison, Wisconsin, United States _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
