Default value for Bit does not work for larger values

 CREATE TABLE user_subscribe (
id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
uid char(50) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '' COMMENT '用户ID',
type tinyint(4) NOT NULL DEFAULT '0' COMMENT '-1自选股，-3关键词，-21自由组合，-22行业组合，-23概念组合，-4分析师，-5研究号',
content bit(8) DEFAULT b'11111111' COMMENT '5个标志位，保留3个（沪深、港股、美股、基金、债券，)',
PRIMARY KEY (id),
KEY uid_type (uid,type)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='订阅分组表';