问查看mysql请求是否为Null、空集或其中包含某些内容

EN

function checkKey(key, cb) {
    var activated = "";
    var sqlcheck = "SELECT activated from authentification where discord_key = ?";
    console.log("in function");
    DB.query(sqlcheck, [key], function (err, result) {
        if (err) throw (err);
        if (result[0] && result[0].activated) {
            activated = result[0].activated;
            console.log("filled key");
        } else {
            activated = false;
            console.log("empty key");
        }
        cb(activatedkey(activated));
        //return (activatedkey(activated));
    })
}