connection.query('INSERT INTO user VALUES (12,' + req.body.text1 + ',' + req.body.text2 + ')'' , function () {...

var data = {ИмяСтолбца1: 1, ИмяСтолбца2: 'Column 2', ИмяСтолбца3: 'Column 3'};
var query = connection.query('INSERT INTO user SET ?', data, function () {...});