You can attach the query executed to your err object when an error occurs:
var q = mysql.query('SELECT `name` FROM `pokedex` WHERE `id` = ?', [ 25 ], function (err, result) {
if (err) {
// Table 'test.pokedex' doesn't exist
err.query = q.sql; // SELECT `name` FROM `pokedex` WHERE `id` = 25
callback(err);
}
else {
callback(null, result);
}
});