>Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im >Auftrag von Jens Alfke >> On Feb 12, 2020, at 5:30 AM, Hick Gunter <h...@scigames.at> wrote: >> >> This is documented here https://sqlite.org/partialindex.html >> <https://sqlite.org/partialindex.html> and here >> https://sqlite.org/queryplanner.html >> <https://sqlite.org/queryplanner.html> >> >> Specifically, SQLIte does not prove theorems in first-order logic. > >Thanks — I hadn't seen the section "Queries Using Partial Indexes" before, and >it gives more detail about how the matching is done. >However, it seems that >my query does match one of the rules: > > "If W [the query's WHERE clause] is AND-connected terms > and X [the index's WHERE clause] is OR-connected terms > and if any term of W appears as a term of X, > then the partial index is usable." > >Here W = (expr1 > val1 OR expr2 > val2) AND expr3 and X = expr3, which is a >degenerate case of one OR-connected term. > >So I'm not sure why the indexes aren't useable, unless there are limitations >of the actual rule that aren't described in that English text.
My guess ist hat SQLite is looking at the "expr1>val1" and "expr2>val2" terms respectively, which don't have a reference to expr3, and thus concludes that the indices are not usable. However, "expr1>val1 AND expr3" clearly matches the rule and thus should use the index. ___________________________________________ Gunter Hick | Software Engineer | Scientific Games International GmbH | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 1 80100 - 0 May be privileged. May be confidential. Please delete if not the addressee. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
