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DROP TABLE IF EXISTS t1;
SELECT IF(NULL AND 1, 1, 2), IF(1 AND NULL, 1, 2);
IF(NULL AND 1, 1, 2) IF(1 AND NULL, 1, 2)
2 2
SELECT NULL AND 1, 1 AND NULL, 0 AND NULL, NULL and 0;
NULL AND 1 1 AND NULL 0 AND NULL NULL and 0
NULL NULL 0 0
create table t1 (a int);
insert into t1 values (0),(1),(NULL);
SELECT * FROM t1 WHERE IF(a AND 1, 0, 1);
a
0
NULL
SELECT * FROM t1 WHERE IF(1 AND a, 0, 1);
a
0
NULL
SELECT * FROM t1 where NOT(a AND 1);
a
0
SELECT * FROM t1 where NOT(1 AND a);
a
0
SELECT * FROM t1 where (a AND 1)=0;
a
0
SELECT * FROM t1 where (1 AND a)=0;
a
0
SELECT * FROM t1 where (1 AND a)=1;
a
1
SELECT * FROM t1 where (1 AND a) IS NULL;
a
NULL
SET @a=0, @b=0;
SELECT * FROM t1 WHERE NULL AND (@a:=@a+1);
a
SELECT * FROM t1 WHERE NOT(a>=0 AND NULL AND (@b:=@b+1));
a
SELECT * FROM t1 WHERE a=2 OR (NULL AND (@a:=@a+1));
a
SELECT * FROM t1 WHERE NOT(a=2 OR (NULL AND (@b:=@b+1)));
a
SELECT @a, @b;
@a @b
0 6
DROP TABLE t1;
drop table if exists t;
create table t(a int, b int);
insert into t values(null, null), (0, null), (1, null), (null, 0), (null, 1), (0, 0), (0, 1), (1, 0), (1, 1);
select ifnull(A, 'N') as A, ifnull(B, 'N') as B, ifnull(not A, 'N') as nA, ifnull(not B, 'N') as nB, ifnull(A and B, 'N') as AB, ifnull(not (A and B), 'N') as `n(AB)`, ifnull((not A or not B), 'N') as nAonB, ifnull(A or B, 'N') as AoB, ifnull(not(A or B), 'N') as `n(AoB)`, ifnull(not A and not B, 'N') as nAnB from t;
A B nA nB AB n(AB) nAonB AoB n(AoB) nAnB
N N N N N N N N N N
0 N 1 N 0 1 1 N N N
1 N 0 N N N N 1 0 0
N 0 N 1 0 1 1 N N N
N 1 N 0 N N N 1 0 0
0 0 1 1 0 1 1 0 1 1
0 1 1 0 0 1 1 1 0 0
1 0 0 1 0 1 1 1 0 0
1 1 0 0 1 0 0 1 0 0
select ifnull(A=1, 'N') as A, ifnull(B=1, 'N') as B, ifnull(not (A=1), 'N') as nA, ifnull(not (B=1), 'N') as nB, ifnull((A=1) and (B=1), 'N') as AB, ifnull(not ((A=1) and (B=1)), 'N') as `n(AB)`, ifnull((not (A=1) or not (B=1)), 'N') as nAonB, ifnull((A=1) or (B=1), 'N') as AoB, ifnull(not((A=1) or (B=1)), 'N') as `n(AoB)`, ifnull(not (A=1) and not (B=1), 'N') as nAnB from t;
A B nA nB AB n(AB) nAonB AoB n(AoB) nAnB
N N N N N N N N N N
0 N 1 N 0 1 1 N N N
1 N 0 N N N N 1 0 0
N 0 N 1 0 1 1 N N N
N 1 N 0 N N N 1 0 0
0 0 1 1 0 1 1 0 1 1
0 1 1 0 0 1 1 1 0 0
1 0 0 1 0 1 1 1 0 0
1 1 0 0 1 0 0 1 0 0
drop table t;
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