| Code : 
 DROP TABLE A;DROP TABLE B; CREATE TABLE A(    A1 INT NOT NULL,    A2 VARCHAR NOT NULL,    DATE DATE NOT NULL); INSERT INTO A VALUES(1, 'X;Y;Z', '2023-03-29');INSERT INTO A VALUES(2, 'K;L;M', '2023-04-21'); CREATE TABLE B(    B1 INT NOT NULL,    B2 VARCHAR NULL,    B3 VARCHAR NULL,    B4 VARCHAR NOT NULL); INSERT INTO B VALUES(1, 'X', NULL, 'true');INSERT INTO B VALUES(2, 'Y', NULL, 'true');INSERT INTO B VALUES(3, NULL, 'Z', 'true');INSERT INTO B VALUES(4, NULL, 'K', 'false');INSERT INTO B VALUES(5, NULL, 'L', 'false');INSERT INTO B VALUES(6, 'M', NULL, 'false');
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