Currently I have road code’s name and road’s code being displayed side by side.
E.g: X123-Highway
but when the road name is not present it displays road code-road code or vice versa as road name-road name.
But i want to display only road name or road code when only one is present.

[@scale < 8k] {
    label: [code]"-"[name];
    label-anchor: 0.5 0.5;
    font-fill: black;
    font-weight: bold;
    label-follow-line: true;
    halo-color: #FFFFFF;
    halo-radius: 2;
}

[@scale < 8k] {
    label: [code is Not Null][name is Not Null] ? [code]" - "[name] : [code is Not Null] ? [code] : [name];
    label-anchor: 0.5 0.5;
    font-fill: black;
    font-weight: bold;
    label-follow-line: true;
    halo-color: #FFFFFF;
    halo-radius: 2;
}