--! qt:dataset:src | |
CREATE TABLE t_test( | |
a tinyint | |
); | |
INSERT INTO t_test VALUES | |
(0), (1), (2), (3), (4), (5), (6), (7), (8), (9); | |
select 1 from (select count(distinct a) from t_test) x; | |
select b from (select count(distinct a) b from t_test) x; | |
explain cbo select 1 from (select count(distinct a) from t_test) x; | |
explain cbo select b from (select count(distinct a) b from t_test) x; | |
explain select 1 from (select count(distinct a) from t_test) x; | |
explain select b from (select count(distinct a) b from t_test) x; |