各位大神，这是什么问题？
mysql> CREATE TABLE tb6)
-> id SMALLINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
-> username VARCHAR(20) NOT NULL UNIQUE KEY,
-> sex ENUM('1','2','3') DEFAULT '3'
-> );
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 ')
id SMALLINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
username VARCHAR(20) NOT NULL' at line 1
mysql>
