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CREATE TABLE t1 (f1 BIT) ENGINE=InnoDB;
INSERT INTO t1 VALUES (NULL),(0),(b'1');
SELECT f1 IS NULL, f1 = b'1' FROM t1;
f1 IS NULL f1 = b'1'
1 NULL
0 0
0 1
DELETE FROM t1 WHERE f1 = b'1';
UPDATE t1 SET f1 = b'1' WHERE f1 IS NULL;
UPDATE t1 SET f1 = 1 WHERE f1 = b'0';
SELECT f1 IS NULL, f1 = b'1' FROM t1;
f1 IS NULL f1 = b'1'
0 1
0 1
CREATE TABLE t2 (f1 BIT) ENGINE=InnoDB;
INSERT INTO t2 VALUES (NULL);
SET AUTOCOMMIT=OFF;
START TRANSACTION;
UPDATE t2 SET f1 = 0 WHERE f1 IS NULL;
SET AUTOCOMMIT=OFF;
START TRANSACTION;
UPDATE t2 SET f1 = 1 WHERE f1 IS NULL;
COMMIT;
COMMIT;
ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
DROP TABLE t1;
DROP TABLE t2;
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