DROP TABLE IF EXISTS t7;
SET sql_mode='NO_ENGINE_SUBSTITUTION';
Warnings:
Warning	3090	Changing sql mode 'NO_AUTO_CREATE_USER' is deprecated. It will be removed in a future release.
CREATE TABLE t7(c1 ENUM('a','abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij') NULL);
INSERT INTO t7(c1) VALUES(NULL);
INSERT INTO t7(c1) VALUES('');
Warnings:
Warning	1265	Data truncated for column 'c1' at row 1
INSERT INTO t7(c1) VALUES('a');
INSERT INTO t7(c1) VALUES('abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij');
INSERT INTO t7(c1) VALUES('abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij');
Warnings:
Warning	1265	Data truncated for column 'c1' at row 1
SELECT * FROM t7;
c1
NULL

a
abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij

SELECT COUNT(c1) AS null_rows FROM t7 WHERE c1 IS NULL;
null_rows
0
DROP TABLE t7;
SET sql_mode=default;