cannot find node js module mysql - mysql

Question

when i enter npm start in the cmd i got that error:
Error: Cannot find module 'mysql'
at Function.Module._resolveFilename (module.js:547:15)
at Function.Module._load (module.js:474:25)
at Module.require (module.js:596:17)
at require (internal/module.js:11:18)
at Object.<anonymous> (C:\fmanagement\db_mysql\dbconnection.js:1:75)
at Module._compile (module.js:652:30)
at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! fmanagement#1.0.0 start: node ./bin/www
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the fmanagement#1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\Flavio Luiz\AppData\Roaming\npm-cache_logs\2018-08-16T23_51_52_867Z-debug.log
after that im install mysql with
npm install -g mysql
and that is my dbconnection.js:
var mysql = require('mysql');
var connection=mysql.createPool({
host:'jdbc:mysql://localhost:3306/',
user:'root',
password:'',
database:'fmanagement'
});
module.exports=connection;
im newbie with node js. im doing something wrong?