async-db.js

const mysql = require('mysql')

const pool = mysql.createPool({

  host     :  '127.0.0.1',

  user     :  'root',

  password :  '123456',

  database :  'my_database'

})

let query = function( sql, values ) {

  return new Promise(( resolve, reject ) => {

    pool.getConnection(function(err, connection) {

      if (err) {

        reject( err )

      } else {

        connection.query(sql, values, ( err, rows) => {

          if ( err ) {

            reject( err )

          } else {

            resolve( rows )

          }

          connection.release()

        })

      }

    })

  })

}

module.exports = { query }

//使用
const { query } = require('./async-db')

async function selectAllData( ) {

  let sql = 'SELECT * FROM my_table'

  let dataList = await query( sql )

  return dataList

}

async function getData() {

  let dataList = await selectAllData()

  console.log( dataList )

}

getData()