Mysql, saving query result

Question

In all tutorials I searched the web, they print the rows/result using console.log the from the mysql query. In my case, I want to store that value to manipulate it in a function. The problem is that node doesn't wait. Can you help me in catching the rows in such example? How can I store the rows in a variable?

con.connect(function (err) {
  if (err) throw err;
  con.query("SELECT * FROM customers", function (err, result) {
    if (err) throw err;
    console.log(result);
  });
});

I tested one of the solutions but I got [] when trying to get result/rows out of the function. I want to use the result in the savedServices: [] see below:

i know it, but how to apply it, please make an answer to mark it. — Abdulrhman Alsri
– Abdulrhman Alsri, Commented Mar 11, 2018 at 12:44
Express not waiting doesn't have anything to do with express. It's related to node. Wrap this in a function and callback with results, then do whatever you need with the result, store it in a variable or whatnot. — ralphtheninja
– ralphtheninja, Commented Mar 11, 2018 at 22:45
Also, stop throwing errors and call back with the errors instead. If you don't, you'll have problems handling errors in your application. — ralphtheninja
– ralphtheninja, Commented Mar 11, 2018 at 22:46

Aefits · Accepted Answer · 2018-03-13 09:03:39Z

2

Give a fresh start with a simple project

Follow below commands

mkdir testdb
cd testdb
npm install --save mysql
npm install --save async

Create a test.js file

vim text.js

Now put below code in the test.js file

var mysql = require('mysql');
var async = require('async');

var con = mysql.createConnection({
  host: "localhost",
  database: "mydb",
  user: "user",
  password: "pass"
});

var myrows = [];

async.waterfall([
    function(callback) {
        con.connect(function(err) {
        if (err) throw err;
        console.log("Connected!");
        var sql = 'select * from users limit 5';
        con.query(sql, function (err, result) {
          if (err) throw err;

          result.forEach(function(item) {
            //console.log(item);
            myrows.push(item);
          });
          callback(null, myrows);
        });
      });
    }
],
// optional callback
function(err, myrows) {
    console.log("myrows:::");
    console.log(myrows);
});

now test the file

node test.js

You should see results like this:

Connected!
Result: [object Object],[object Object],[object Object],[object Object],[object Object]

Hope this helps!

edited Mar 13, 2018 at 9:03

answered Mar 13, 2018 at 6:25

Aefits

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8 Comments

Abdulrhman Alsri Over a year ago

I appreciate that, but you didn't store the results/rows in a variable, which I state clearly in the post!

Abdulrhman Alsri Over a year ago

thank you for interaction. I wanted to show the result to you on a screenshot, so I updated the post with an screenshot. please check it and let us keep going on it to solve it. thank you.

Abdulrhman Alsri Over a year ago

it is async issue.

Aefits Over a year ago

Yes in this case you will need to use async. Have a look at this stackoverflow.com/a/30973427/1225070

Abdulrhman Alsri Over a year ago

i am tired of applying that and couldn't achieve it, if that easy for you, please update your answer with the fix. I want to see how applied. I want to mark your answer as best answer.

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