//連接數據庫var mysql = require('mysql');var pool = mysql.createPool({  host: 'localhost',  user: 'root',  password: 'gfdfsdf34r34r',  database:'caiji'});module.exports = function(sql, callback) {  pool.getConnection(function(conn_err, conn) {    if(conn_err) {      callback(err,null,null);    } else {      conn.query(sql, function(query_err, rows, fields) {        conn.release();        callback(query_err, rows, fields);      });    }  });};

var query = require("./mysql.js");query(sql, function(err, rows, fields) {  console.log(rows);});