SET count_distinct_implementation = 'uniq'; SELECT count(DISTINCT x) FROM (SELECT number % 123 AS x FROM system.numbers LIMIT 1000); SELECT count(DISTINCT x, y) FROM (SELECT number % 11 AS x, number % 13 AS y FROM system.numbers LIMIT 1000); SET count_distinct_implementation = 'uniqCombined'; SELECT count(DISTINCT x) FROM (SELECT number % 123 AS x FROM system.numbers LIMIT 1000); SELECT count(DISTINCT x, y) FROM (SELECT number % 11 AS x, number % 13 AS y FROM system.numbers LIMIT 1000); SET count_distinct_implementation = 'uniqExact'; SELECT count(DISTINCT x) FROM (SELECT number % 123 AS x FROM system.numbers LIMIT 1000); SELECT count(DISTINCT x, y) FROM (SELECT number % 11 AS x, number % 13 AS y FROM system.numbers LIMIT 1000);