How can I check if an email already is in Mysql database on NodeJs? I'm using the following code

app.use(express.static(__dirname   '/public'));
router.get('/',function(req,res) {
    res.sendFile(path.join(__dirname   '/public/html/index.html'));
    var email = req.query.email;
    if (email != null) {
        conn.query('INSERT INTO users (email) VALUES (?)', [email], function(err, result) {
            if (err) throw err;
            console.log('1 record inserted')            
        })
    }
});

CodePudding user response：

This is an example from a store stay project I had. I use this method because it is convenient for me.

const [isItemExist] = await SQL(`
    SELECT * FROM products WHERE products.id =${Item} `)
    

    if (!isItemExist) {
        return res.send({ err: 'product not found' })
    }

CodePudding user response：

Check if e-mail exist only do insert if it doesn't:

    router.get('/', function(req, res){
        res.sendFile(path.join(__dirname   '/public/html/index.html'));
            var email = req.query.email;
    
            if (email != null) {
            conn.query('SELECT * FROM users WHERE email=?', [email], function(err, result) {
                if (err) throw err;
                if (result.length > 0) {
                    console.log('Email already exist')
                }
                else {
                    conn.query('INSERT INTO users (email) VALUES (?)', [email], function(err, result) {
                if (err) throw err;
                console.log('1 record inserted')
                    })}
                })
            }
        })