NodeJS MySql db.query command always running last - mysql

Question

In my simple code which uses NodeJS and Express Framework along with MySql as my database, I made a simple query to the database. This is shown below vvv
app.get('/getusers', (req, res) => {
console.log('Start line')
let sql = 'SELECT * FROM users';
let query = db.query(sql, (err, results) => {
if(err) throw err;
console.log(results);
res.send('Posts fetched...');
});
console.log('End line')
});
In the terminal, the code's output is as shown below vvv
Start line
End line
[
RowDataPacket {
id: 1,
usnm: 'admin',
pswd: 'securePassword'
},
RowDataPacket {
id: 2,
usnm: 'user',
pswd: 'superSeurePassword'
}
]
Why did the lines "Start line" and "End line" run first, then the db.query command run later?
How can I fix my code so that it runs in order?

Answer 1

A database query is an asyncronous operation, meaning that you should await the result of the query:
const util = require('util');
const query = util.promisify(db.query).bind(db); // Make db.query able to be awaited
app.get('/getusers', async (req, res) => { // declare your function as 'async'
console.log('Start line')
let sql = 'SELECT * FROM users';
// Convert your callback to an try/catch block, so we could catch the error
try {
const results = await query(sql) // Your results will be returned straight here
console.log(results);
res.send('Posts fetched...');
} catch (err) { // If some error happens, it will be catched here
throw err;
}
console.log('End line')
});