MySQL 8.0

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create table test (foo char(5));
insert into test (foo) values ('A');
insert into test (foo) values ('B');
insert into test (foo) values ('C');
insert into test (foo) values (NULL); -- null
insert into test (foo) values (''); -- empty
insert into test (foo) values (' '); -- white space
insert into test (foo) values ('False');  -- boolean strings
insert into test (foo) values ('false'); 
insert into test (foo) values ('0'); 
insert into test (foo) values ('True'); 
insert into test (foo) values ('true'); 
insert into test (foo) values ('1'); 

-- causes the batch to fail
-- insert into test (foo) values ('\0');  -- null terminator
select foo, !foo from test;


foo
!foo


A
1

B
1

C
1

null
null


1


1

False
1

false
1

0
1

True
1

true
1

1
0


select foo, !foo from test where !foo


foo
!foo


A
1

B
1

C
1


1


1

False
1

false
1

0
1

True
1

true
1


select foo, !foo from test where foo


foo
!foo


1
0