Beginner guide to connect to MySQL with NodeJS
Start a Node JS project
> mkdir nodejs-mysql> cd nodejs-mysql> npm init -yinstall mysql package
> npm i --save mysqlcreate a server.js file
> touch server.jsOpen nodejs-mysql in your favorite editor and add following code to server.js
const mysql = require('mysql')
// create connection object for DB, you can get all below values from the connection stringconst connectionConfig = { host: '<replace_with_your_db_server>', // if mysql is running locally it may be 'localhost' user: '<replace_with_user_id_having_access_to_your_db>', password: '<replace_with_db_password>', database: '<default_database_to_connect>'}// initialize with connection configconst db = mysql.createConnection(connectionConfig)
// connect to the serverdb.connect(function(err){ if(err) throw err console.log("MySQL DB connected successfully!")})
// create query for your dbconst sql =`select * from dbName.tableName`;
// query your db db.query(sql, function(err,result){ if(err) throw err console.log(result) Object.keys(result).forEach((key)=>{ console.log(result[key]) }) })
// don't forget to close your connection db.end(err=>{ if(err) throw err console.log('Connection to MySQL is successfully closed') })}To run code, run below command in terminal
> node server.jsYou should see the result of your query in the terminal. To save query result in a file you can use csv-stringify package. Here is small code snippet for the same
...const fs = require('fs');const stringify = require('csv-stringify');......
// queryResult is a string value filtered after querying databasestringify(queryResult, function(err, output) { fs.writeFile('query.csv', output, 'utf8', function(err) { if (err) { console.log('Some error occured - file either not saved or corrupted file saved.'); } else { console.log('It\'s saved!'); } }); });