Hi all, I've ran into an optimisation problem with a double-left join that works as an "either" clause.
The query is as follows: SELECT * FROM a LEFT JOIN b ON <cond> LEFT JOIN c ON <cond> WHERE b.someId IN (1,2,3) OR c.someId IN (4,5) This results in a bloated execution plan: SEARCH a SEARCH SUBQUERY 1 USING AUTOMATIC COVERING INDEX SEARCH SUBQUERY 2 USING AUTOMATIC COVERING INDEX However, the semantically equivalent: SELECT * FROM a LEFT JOIN b ON <cond> AND b.someId IN (1,2,3) LEFT JOIN c ON <cond>AND c.someId IN (4,5) WHERE b.someId IS NOT NULL OR c.someId IS NOT NULL Gets the proper execution plan: SEARCH b SEARCH c EXECUTE LIST SUBQUERY -- Sent from: http://sqlite.1065341.n5.nabble.com/ _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
