NodeJs Mysql returns empty result

Question

I have api's that queries the data and returns the results in json format. if i call the query inside api.get and set the res.send(rows) it is working fine but i need to call that same method in different methods so I thought I could write it outside and call that method whenever it is needed. but the result returns empty when it is outside.

var customerRows[]
app.get('/customers', function(req, res) {
    getCustomers();
    res.json({
        customers : customerRows
    });
});

function getCustomersQuery(callback) {
    var customersDataQuery = mysqlConnection.query('SELECT * from customer_info', function(err, rows, fields) {
        if (!err) {
            if (rows) {
                callback(null, rows);
            }
        } else {
            callback(err, null);
            console.log('Error while performing Query.');
        }
    });
}

function getCustomers() {
    getCustomersQuery(function(err, result) {
        if (err) {
            console.log(err);
        } else {
            customerRows.push(result);
            console.log(customerRows)//prints values
        }
    });
    console.log("Result : "+customerRows);//prints empty
}

I'm trying to set the result to my global variable customerRows but it returns empty.

Answer 1

use this code

app.get('/customers', function(req, res) {    
    getCustomersQuery(function(err, result) {
        if (err) {
            console.log(err);
        }        
        res.json({
            customers : result
        });
    });
});

function getCustomersQuery(callback) {
    var customersDataQuery = mysqlConnection.query('SELECT * from customer_info', function(err, rows, fields) {
        if (!err) {
            if (rows) {
                callback(null, rows);
            }
        } else {
            callback(err, null);
            console.log('Error while performing Query.');
        }
    });
}