1--disable_warnings 2DROP TABLE IF EXISTS t7; 3--enable_warnings 4SET sql_mode='NO_ENGINE_SUBSTITUTION'; 5CREATE TABLE t7(c1 SET('a','abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij') NULL); 6INSERT INTO t7(c1) VALUES(NULL); 7INSERT INTO t7(c1) VALUES(''); 8INSERT INTO t7(c1) VALUES('a'); 9INSERT INTO t7(c1) VALUES('abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij'); 10INSERT INTO t7(c1) VALUES('abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij'); 11INSERT INTO t7(c1) VALUES('a,abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij'); 12SELECT * FROM t7; 13SELECT COUNT(c1) AS null_rows FROM t7 WHERE c1 IS NULL; 14DROP TABLE t7; 15SET sql_mode=default; 16