$tupleVariantType = Variant<Int32, String>;

$optionalData = [
    <|variantValue: Just(Variant(1,       "0", $tupleVariantType))|>,
    <|variantValue: Nothing(OptionalType($tupleVariantType))|>,
    <|variantValue: Just(Variant("hello", "1", $tupleVariantType))|>,
];

SELECT variantValue.0 AS intAlternative, variantValue.1 AS strAlternative FROM as_table($optionalData);