text: set max_threads = 16;
  SELECT number, number + 3 FROM numbers_mt (1000) where number > 5 order by number desc limit 3;
  SELECT number%3 as c1, number%2 as c2 FROM numbers_mt (10) order by c1 desc, c2 asc;
  EXPLAIN SELECT number%3 as c1, number%2 as c2 FROM numbers_mt (10) order by c1, number desc;
  SELECT number%3 as c1, number%2 as c2 FROM numbers_mt (10) order by c1, number desc;
  
  create table t1(id int);
  insert into t1 select number as id from numbers(10);
  select * from t1 order by id asc limit 3,3;
  select * from t1 order by id desc limit 3,3;
  drop table t1;
  
  -- sort with null
  SELECT number, null from numbers(3) order by number desc;
  