On Thu, 6 Jun 2013 10:53:55 -0400 Richard Hipp <[email protected]> wrote:
> On Thu, Jun 6, 2013 at 10:52 AM, Gabriel Corneanu <[email protected] > > wrote: > > > Strange is, count(*) uses the cover index for a but "select count(a)" does > > NOT use the same cover index... > > > > count(a) has to check for NULL values of a, which are not counted. > count(*) does not. If I understand well , select count(a) from t = (select count(*) from t) - (select count(*) from t where t.a = NULL) and both selects will use cover indexs, doesn't it? > -- > D. Richard Hipp > [email protected] --- --- Eduardo Morras <[email protected]> _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
