MySQL 8.0

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create table test (foo int);
insert into test (foo) values (-2);
insert into test (foo) values (-1);
insert into test (foo) values (0);
insert into test (foo) values (1);
insert into test (foo) values (2);
insert into test (foo) values (NULL);
select foo, !foo from test;


foo
!foo


-2
0

-1
0

0
1

1
0

2
0

null
null


select foo, !foo from test where !foo


foo
!foo


0
1


select foo, !foo from test where foo


foo
!foo


-2
0

-1
0

1
0

2
0

foo	!foo
-2	0
-1	0
0	1
1	0
2	0
null	null