On Sun, Nov 15, 2009 at 11:41 AM, P Kishor <punk.k...@gmail.com> wrote: > 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. > >
There are certain conditions in which a LIKE (or GLOB) term will be transformed by the query planner into an equivalent expression to allow the use of indices. Please see http://www.sqlite.org/optoverview.html for a more in-depth discussion. >> 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? >> _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
