如何在变量中存储Node mysql查询? [英] How to store Node mysql query in a variable?

问题描述

我正在使用节点mysql连接到外部数据库，并且可以 console.log 查询结果，但是当我尝试返回数据时，我得到 Promise未决.

I'm using node mysql to connect to an external DB and I can console.log the query results but when I try to return the data I get Promise pending.

这是函数-

export function get_info() {

    var mysql = require('mysql');
    var connection = mysql.createConnection({
        host: 'xxxxxx',
        user: 'bob',
        port: 'xxxx',
        password: 'bob',
        database: 'li_webform'
    });

    connection.connect(function (err) {
        if (err) throw err;
        connection.query("SELECT Name FROM webform", function (err, result) {
            if (err) throw err;
            //console.log(result); **This works**
            //console.log(result[0].Name);
            return result;
        });
    });
}

我正试图像这样将变量设置为等于返回值

I'm trying to set a variable equal to the return value like this

var newVar = get_info();
console.log(newVar);

但是我得到了未完成的诺言.我相信这与JavaScript的异步性质有关.我已尝试按照此帖子如何正确返回mysql和Node一起导致的结果?但无法正常工作.

but I got the promise pending note. I believe this has something to do with the Asynchronous nature of JavaScript. I've tried following this post How to properly return a result from mysql with Node? but can't get it working.

这是我按照该帖子尝试的内容

Here is what I tried following that post

export function get_info(callback) {

    var mysql = require('mysql');
    var connection = mysql.createConnection({
        host: 'xxxxx',
        user: 'bob',
        port: 'xxxxxx',
        password: 'bob',
        database: 'li_webform'
    });

    connection.connect(function (err) {
        if (err) throw err;
        connection.query("SELECT Name FROM webform", function (err, result) {
            if (err) throw err;
            //console.log(result);
            //console.log(result[0].Name);
            return callback(result);
        });
    });
}

然后我尝试通过

var stuff_i_want = '';

get_info(function (result) {
    stuff_i_want = result;
    console.log(stuff_i_want);
});

但是我没有输出

编辑**这是新尝试

export function get_info() {

    var mysql = require('mysql');
    var connection = mysql.createConnection({
        host: 'xxxx',
        user: 'bob',
        port: 'xxxxxx',
        password: 'bob',
        database: 'li_webform'
    });

    connection.connect(function (err) {
        if (err) throw err;
        connection.query("SELECT Name FROM webform", function (err, result) {
            if (err) throw err;
            //console.log(result);
            //console.log(result[0].Name);
            return result;
        });
    });
}

第二部分

    get_info().then((callbackData)=>{
   console.log("Data: ", callbackData)
 }).catch((error)=>{
    console.log("Error", error)
 });

推荐答案

该函数返回一个Promise.您可以这样处理:

The function returns a promise. You can handle it like this:

 get_info().then((callbackData)=>{
   console.log("Data: ", callbackData)
 }).catch((error)=>{
    console.log("Error", error)
 });

这篇关于如何在变量中存储Node mysql查询?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！