Register panel MySQL

[Snoowy]

Hello! I started making a account system, however, I missed the registration. How do I do it just to register once? Thank you for help!

MySQL Script

	local connection = nil
addEventHandler("onResourceStart",resourceRoot,function(resource)
        connection = dbConnect("mysql","dbname=ig_mta;host=localhost;port=3306;","root","martinka02")
        if connection then
            outputDebugString(getResourceName(resource) .. " : connected to database.")
            return true
        else
            outputDebugString(getResourceName(resource) .. " : Unable to connect with database. Please contact Developer.")
            return false
        end
    end
)
	function _Query( ... )
    if connection then
        local query = dbQuery(connection, ... )
        local result = dbPoll(query,-1)
        return result
    else
        return false
    end
end
	function _QuerySingle(str,...)
    if connection then
        local result = _Query(str,...)
        if type(result) == 'table' then
            return result[1]
        end
    else
        return false
    end
end
	function _Exec(str,...)
    if connection then
        local query = dbExec(connection,str,...)
        return query
    else
        return false
    end
end
	

Account System - Server Side

	 
	addEvent("loginPlayer", true)
function loginPlayer(player, username, password, serial)
    local check = exports.mta_connection:_QuerySingle("SELECT * FROM accounts WHERE username = ?",username)
    if check then
        local serial = getPlayerSerial(player)
        local checkPass = check.password
        local checkSerial = check.serial
        if ( checkSerial == serial ) then
            if (checkPass == password) then
                logIn(player,tostring(username),tostring(password))
                outputDebugString("User is loggined!")
                triggerClientEvent(player,"showHide",getRootElement())
            else
                exports["notices"]:addNotification(root,"Hibás felhasználónév/jelszó!",'error')
            end
        else
            exports["notices"]:addNotification(root,"Ez a felhasználó nem ehhez a számítógéphez van társítva!",'error')
        end
    else
        exports["notices"]:addNotification(root,"Hibás felhasználónév/jelszó!",'error')
    end
end
addEventHandler("loginPlayer", getRootElement(),loginPlayer)
	addEvent("registerPlayer", true)
function registerPlayer(player, username, password, email, serial, ip, money)
    if ( checkSerial ~= serial ) then
        local account = getAccount(username)
        if account == false then
            local ip = getPlayerIP(player)
            local money = 100
            exports.mta_connection:_Exec("INSERT INTO accounts(username,password,email,serial,ip,money) values (?,?,?,?,?,?)",username,password,email,serial,ip,money)
            local addAccount = addAccount(tostring(username), tostring(password))
            if addAccount then
                exports["notices"]:addNotification(root,"A felhasználó sikeresen létrehozva!",'succes')
            else
                exports["notices"]:addNotification(root,"Hiba történt! Keress fel egy fejlesztőt a problémával kapcsolatban!",'error')
            end
        else
            exports["notices"]:addNotification(root,"Ez a felhasználónév már foglalt! Válassz másikat!",'error')
        end
    else
        exports["notices"]:addNotification(root,"Ehhez a számítógéphez van felhasználó társítva!",'error')
    end
end
addEventHandler("registerPlayer", getRootElement(), registerPlayer)