show variables like 'version';

use test42908;

explain SELECT COUNT(DISTINCT c) from sbtest where id between 1 and 1000000 order by c;
SELECT COUNT(DISTINCT c) from sbtest where id between 1 and 1000000 order by c;

explain SELECT DISTINCT c from sbtest where id between 1 and 100000 order by c;
SELECT DISTINCT c from sbtest where id between 1 and 100000 order by c;

explain SELECT DISTINCT c from sbtest where id between 100000 and 500000 order by c;
SELECT DISTINCT c from sbtest where id between 100000 and 500000 order by c;

explain SELECT DISTINCT c from sbtest where id between 100000 and 1000000 order by c;
SELECT DISTINCT c from sbtest where id between 100000 and 1000000 order by c;

explain SELECT DISTINCT c from sbtest where id between 1 and 1000000 order by c;

SELECT DISTINCT c from sbtest where id between 1 and 1000000 order by c;