db.js

const mysql = require('mysql')

const pool = mysql.createConnection({
    host: config.db.host,
    user: config.db.user,
    password: config.db.password,
    database: config.db.database,
});

class DB {
   static query(sql, values, options) {
   // ...
   }
}

DB.pool = pool;

module.exports = DB;

getInfo.js

const DB = require('./db.js')

const getInfo = async(param1, param2) => {
  const sql = `
    SELECT * 
    FROM ?? 
    LEFT JOIN ?? USING(??)
    WHERE ?? = ?`
  const args = ['table1', 'table2', 'name', 'id', param1]
  
  return DB.query(sql, args)
}