ClickHouse/tests/queries/0_stateless/01747_transform_empty_arrays.sql

SELECT *
FROM
(
    WITH

        (
            SELECT groupArray(a)
            FROM
            (
                SELECT 1 AS a
            )
        ) AS keys,

        (
            SELECT groupArray(a)
            FROM
            (
                SELECT 2 AS a
            )
        ) AS values
    SELECT *
    FROM
    (
        SELECT 1 AS a
    )
    WHERE transform(a, keys, values, 0)
) AS wrap;