SET SQL_MODE="TRADITIONAL,ANSI"; DROP TABLE IF EXISTS t7; CREATE TABLE t7(c1 SET('a','abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij') NULL); INSERT INTO t7(c1) VALUES(NULL); INSERT INTO t7(c1) VALUES(''); INSERT INTO t7(c1) VALUES('a'); INSERT INTO t7(c1) VALUES('abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij'); INSERT INTO t7(c1) VALUES('abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij'); ERROR 01000: Data truncated for column 'c1' at row 1 INSERT INTO t7(c1) VALUES('a,abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij'); SELECT * FROM t7; c1 NULL a abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij a,abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij SELECT COUNT(c1) AS null_rows FROM t7 WHERE c1 IS NULL; null_rows 0 DROP TABLE t7;