这是你navicat的问题，我用sqlyog测试没问题，你可以换个工具，或者换个高版本的navicat
/*
SQLyog Ultimate v12.3.1 (64 bit)
MySQL - 5.7.25-TiDB-v5.4.3 : Database - pingcap
*/
/*!40101 SET NAMES utf8 */;
/!40101 SET SQL_MODE=‘’/;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 /;
/!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 /;
/!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE=‘NO_AUTO_VALUE_ON_ZERO’ /;
/!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
USE pingcap;
/*Table structure for table system */
DROP TABLE IF EXISTS system;
CREATE TABLE system (
id bigint(20) NOT NULL /*T![auto_rand] AUTO_RANDOM(5) */ COMMENT ‘id’,
name varchar(100) NOT NULL COMMENT ‘系统名称’,
code varchar(50) NOT NULL COMMENT ‘系统标识’,
url varchar(240) DEFAULT NULL COMMENT ‘pc网址’,
wap_url varchar(240) DEFAULT NULL COMMENT ‘m网址’,
description varchar(200) DEFAULT NULL COMMENT ‘系统说明’,
status smallint(6) NOT NULL COMMENT ‘系统状态 1正常，2关闭’,
err_info varchar(200) DEFAULT NULL COMMENT ‘状态说明，系统状态为2时在这里说明’,
create_at bigint(20) DEFAULT ‘0’ COMMENT ‘创建时间’,
update_at bigint(20) DEFAULT ‘0’ COMMENT ‘更新时间’,
PRIMARY KEY (id) /*T![clustered_index] CLUSTERED */,
UNIQUE KEY uniq_system_name_idx (name),
UNIQUE KEY uniq_system_code_idx (code),
KEY key_system_create_at_idx (create_at)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin COMMENT=‘系统表’;
/*Data for the table system */
/*!40101 SET SQL_MODE=@OLD_SQL_MODE /;
/!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS /;
/!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS /;
/!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;