$tupleVariantType = Variant<Int32, Int32>;

$optionalData = [
    <|variantValue: Just(Variant(1, "0", $tupleVariantType))|>,
    <|variantValue: Nothing(OptionalType($tupleVariantType))|>,
    <|variantValue: Just(Variant(2, "1", $tupleVariantType))|>,
];

SELECT Yql::VariantItem(variantValue) AS item FROM as_table($optionalData);