9 digit pandigital number

function is9Pandigital(num)
    -- 9 digit zeroless pandigital
    -- pandigital number is an integer that in a given
    -- base has among its significant digits each digit
    -- used in the base at least once
    numSize = string.len(num)
    result = false

    if numSize == 9 then
        auxi = {}
        for i = 1, numSize do
            table.insert(auxi, tonumber(string.sub(num, i, i)))
        end

        table.sort(auxi)

        sfinal = ""
        for i = 1, #auxi do
            sfinal = sfinal .. auxi[i]
        end

        if sfinal == "123456789" then
            result = true
        end
    end

    return result
end

print(is9Pandigital(932465781))
-- 932465781: true
-- 992465781: false