Description:
data_a(a1, a2, a3, a4) contains 10 rows, when run `select count(*) from data_a_tmp where (not(a1 < 4) is null);` it should returns 0 rows, however it returns 10 rows.
How to repeat:
create table data_a_tmp(a1 float, a2 float, a3 float, a4 float);
insert into data_a_tmp(a1, a2, a3, a4) values (6.97,2.13,4.5,4.0);
insert into data_a_tmp(a1, a2, a3, a4) values (9.52,4.87,5.33,7.21);
insert into data_a_tmp(a1, a2, a3, a4) values (4.69,3.82,5.66,7.22);
insert into data_a_tmp(a1, a2, a3, a4) values (3.8,7.55,5.18,7.82);
insert into data_a_tmp(a1, a2, a3, a4) values (9.95,5.0,5.26,6.09);
insert into data_a_tmp(a1, a2, a3, a4) values (3.98,6.8,5.93,6.8);
insert into data_a_tmp(a1, a2, a3, a4) values (3.3,5.89,5.44,6.22);
insert into data_a_tmp(a1, a2, a3, a4) values (2.07,7.09,3.01,6.82);
insert into data_a_tmp(a1, a2, a3, a4) values (4.98,4.9,3.04,5.11);
insert into data_a_tmp(a1, a2, a3, a4) values (8.98,8.46,5.93,4.28);
select count(*) from data_a_tmp; -- 10 rows
select count(*) from data_a_tmp where (not(a1 < 4)); --6 rows
select count(*) from data_a_tmp where (not(not(a1 < 4))); --4 rows
select count(*) from data_a_tmp where (not(a1 < 4) is null); --10 rows
