On Nov 16, 2009, at 5:14 PM, Tim Romano wrote: > > Do I understand the docs correctly, that if the query statement > contains > a literal string (as distinct from a bound parameter) it doesn't > matter > which function is used to compile the statement and the index WILL be > used provided all of the optimization prerequisites are met? >
SQLite uses a cost-based query planner. The query planner looks at many (hundreds, thousands) of ways of doing the query and selects the one it thinks will get the job done fastest. If the LIKE term is what seems likely (to SQLite) to give the fastest answer, then that is what will be used. And if conditions are as you describe, then probably the LIKE term will seem fastest to SQLite. But there are lots of other considerations and hence no guarantees. One thing that SQLite does guarantee is that it will always make the same query plan choice until you either (1) change the schema, (2) run ANALYZE, (3) change the RHS of the LIKE operator, (4) compile with SQLITE_ENABLE_STAT2 and change binding on other parameters in the query, or (5) change SQLite release versions. So once you get it using LIKE it should always continue using LIKE. D. Richard Hipp d...@hwaci.com _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
