Hello! Nabble is really wonderful resource, because I received answers to all my questions. Sorry now, but I have to ask to help me again (if someone could). I'm not good in sql yet, so if anyone could find a minute to think about optimization of my sql query I'll be very much obliged. I have two sqlite databases (I couldn't store all data in one db because of architecture). In first db there are tables CREATE TABLE mgWordsRelations (id INTEGER PRIMARY KEY, id_norm INTEGER, id_norminrel INTEGER, UNIQUE (id_norm,id_norminrel)) CREATE TABLE mgWordsNorm (id INTEGER PRIMARY KEY, wordnorm INTEGER UNIQUE) In second CREATE TABLE wform (id INTEGER PRIMARY KEY, wordForm TEXT, ancode TEXT, wordNorm INTEGER) I loaded first db and than ATTACH DATABASE 'second.db' AS Lang
I need to execute query SELECT wordForm FROM Lang.wform WHERE (ancode='someAncode') AND (wordNorm IN (SELECT DISTINCT id_norminrel FROM mgWordsRelations WHERE id_norm IN (SELECT wordNorm FROM Lang.wform WHERE wordForm='someWord'))) ORDER BY RANDOM() LIMIT 1 of course it is very slow because of nested queries and ordering by random. How could I optimize it (maybe using UNION or someone else)? Im looking forward to all comments! Thank you! -- View this message in context: http://old.nabble.com/Help-me-please-to-optimize-sql-query-tp26354687p26354687.html Sent from the SQLite mailing list archive at Nabble.com. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users