[求助]这段SQL代码到底错在哪

DROP TABLE IF EXISTS users;
CREATE TABLE users(
'USER_ID' VARCHAR(50) NOT NULL DEFAULT'',
'PASSWORD' VARCHAR(20) NOT NULL DEFAULT'',
'NAME' VARCHAR(8) NOT NULL DEFAULT'',
'SEX' CHAR(6) NOT NULL DEFAULT'male',
'BIRTH' bigint NOT NULL,
'DESCRITION' VARCHAR(256) NOT NULL DEFAULT'',
PRIMARY KEY ('USER_ID')
) ENGINE=InnoDB DEFAULT CHARSET=utf8;




系统显示如下错误信息：
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 ''USER_ID' VARCHAR(50) NOT NULL DEFAULT'',
'PASSWORD' VARCHAR(20) NOT NULL DEF' at line 2