discord.js检查邮件作者id是否在数据库中？

const Discord = require('discord.js');
const mysql = require('mysql');

const client = new Discord.Client();
const dbConnection = mysql.createConnection({
  host: '数据库主机地址',
  user: '数据库用户名',
  password: '数据库密码',
  database: '数据库名',
});

client.on('message', (message) => {
  // 获取邮件作者的id
  const authorId = message.author.id;

  // 查询数据库
  const query = `SELECT * FROM authors WHERE author_id = '${authorId}'`;
  dbConnection.query(query, (error, results) => {
    if (error) {
      console.error('数据库查询错误：', error);
      return;
    }

    if (results.length === 0) {
      console.log('邮件作者id不在数据库中');
    } else {
      console.log('邮件作者id在数据库中');
    }
  });
});

client.login('YOUR_DISCORD_BOT_TOKEN');