Myujth

Using node.js and the mysql module, I am trying to select data from a table, manipulate that data, then insert the manipulate data to another table in the database.

var mysql = require('mysql');

var connection = mysql.createConnection(
host: 'localhost',
user: 'username',
password: 'pass',
database: 'db',
);

var q = 'SELECT * FROM table1';
var data_wanted = ;

connection.query(q, function(err, result) 

 for(var i = 0; i < 100; i++) //let's say there are 100 rows in table1
 var manipulated_data = result + 1;
 data_wanted.push(manipulated_data);
 

);

Ideally, I would take the values in data_wanted and bulk insert it. Something like:

var q2 = 'INSERT into table2 (number) VALUES ?';

connection.query(q2, [data_wanted], function(err, result) 
 //bulk inserts data_wanted
);

However, data_wanted does not take data from the first query.

console.log(data_wanted) //outputs ; still empty, even after 1st query

I believe that this is a scope issue. But I have no idea how to actually solve this problem. I would appreciate help greatly.

It should be this

var q2 = 'INSERT into table2 (number) VALUES (?)';

I think its just the brackets you were missing.

You are using statements so you will have to add more code of course.

I hope I helped.

You can use one query insert all.
This a example:

INSERT INTO users_log (`name`,`address`)
SELECT u.`name`,u.`address`
FROM users u ;

Table users:

Table users_log:

This link documment: https://dev.mysql.com/doc/refman/8.0/en/insert-select.html

The main cause because your code doesn't have connect to database .You must to connect database before when you do query sql. You can refer this way.

 var mysql = require('mysql');

 var connection = mysql.createConnection(
 host: 'localhost',
 user: 'username',
 password: 'pass',
 database: 'db',
 );

 connection.connect(function(err) 
 if (err) throw err;
 console.log("Connected!");
 );

 var q = 'SELECT * FROM table1';
 var data_wanted = ;

 connection.query(q, function(err, result) 
 result.forEach(function(row) 
 console.log(row);
 data_wanted.push(row);
 );
 console.log(data_wanted);
 );