username VARCHAR(20) NOT NULL语法怎么错了?
root@localhost t2>CREATE TABLE tb4(
-> id SMALLINT UNSIGNED PRIMARY KEY
-> username VARCHAR(20) NOT NULL
-> );
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'username VARCHAR(20) NOT NULL
)' at line 3
我用的MySQL 5.7.14版,什么原因出错了?