ALTER DATABASE t_yown_userdb CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
ALTER TABLE t_yown_user CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
alter table t_yown_user modify `NICKNAME` varchar(80) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci COMMENT '昵称';