SQL output undefined when using it outside the function-CodePudding

I am trying to execute SQL results outside it's function. This is my code:

var rows;
var fields;

const connection = await mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: '',
  database: 'root'
});

connection.connect(
    (err) => {
        if(err) {
            console.log(err);
            process.exit(0);
        }
        
        console.log('logged in!');        
    }
);

async function query() {
    [rows, fields] = await connection.execute("SELECT plan FROM users WHERE username = 'onyx'");
    console.log(rows);
}

console.log(rows);
query();

First console.log(rows); gives correct output but once I put it outside the function, I get error undefined.

I know there are questions about this but I need better understanding and explanation about this...

I am using sync now as told but still same problem.

CodePudding user response：

You have an async function query() and you are trying to log 'rows' inside and outside the function, according to your code, you have

console.log(rows);
query();

this way, the log inside the function will surely return an output because it is being filled by the query above it, but if u try to log outside, it will not and that's because u didn't await qeury() to finish.

to get it working:

await query();
console.log(rows)

this way, rows will be filled before logging because you are filling rows with an async function which has to be awaited