On Sat, 1 Feb 2014 11:21:45 -0500 Stephen Chrzanowski <pontia...@gmail.com> wrote:
> Would be interesting to see when and where that single index comes > into play when multiple indexes are defined. create table T (t int primary key, a int , b int); create index Ta on T(a); create index Tb on T(b); select * from T where a < 1 or b < 1 Using one index, pick your poison. You could use Ta or Tb, but for the other half of the OR you'll have to scan the table. So you might as well scan the table and forget about the index. Using two indexes, you can find the matching values in Ta and Tb, and produce results from the union of the two. For 10 rows, the two-index algorithm is likely slower. For a million rows, depending on the cardinality of the data, it could be significantly faster. --jkl _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
