SELECT
    count() AS cnt,
    uniq(number) AS uniq,
    (abs(uniq - cnt) / cnt) * 100 AS uniqError,
    uniqTheta(number) AS uniqTheta,
    (abs(uniqTheta - cnt) / cnt) * 100 AS ThetaError,
    g
FROM
(
    SELECT
        number,
        1 AS g
    FROM numbers_mt(1000000000.)
)
GROUP BY g

┌────────cnt─┬───────uniq─┬─uniqError─┬─uniqTheta─┬─ThetaError─┬─g─┐
│ 1000000000 │ 1001803777 │ 0.1803777 │ 244195952 │ 75.5804048 │ 1 │
└────────────┴────────────┴───────────┴───────────┴────────────┴───┘

┌────────cnt─┬───────uniq─┬─uniqError─┬─uniqTheta─┬─ThetaError─┬─g─┐
│ 1000000000 │ 1001803777 │ 0.1803777 │ 499922124 │ 50.0077876 │ 1 │
└────────────┴────────────┴───────────┴───────────┴────────────┴───┘

┌────────cnt─┬───────uniq─┬─uniqError─┬─uniqTheta─┬─ThetaError─┬─g─┐
│ 1000000000 │ 1001803777 │ 0.1803777 │ 500732911 │ 49.9267089 │ 1 │
└────────────┴────────────┴───────────┴───────────┴────────────┴───┘

-- let's use numbers, not numbers_mt

SELECT
    count() AS cnt,
    uniq(number) AS uniq,
    (abs(uniq - cnt) / cnt) * 100 AS uniqError,
    uniqTheta(number) AS uniqTheta,
    (abs(uniqTheta - cnt) / cnt) * 100 AS ThetaError,
    g
FROM
(
    SELECT
        number,
        1 AS g
    FROM numbers(1000000000.)
)
GROUP BY g

┌────────cnt─┬───────uniq─┬─uniqError─┬─uniqTheta─┬──────────ThetaError─┬─g─┐
│ 1000000000 │ 1001803777 │ 0.1803777 │ 995807422 │ 0.41925779999999996 │ 1 │
└────────────┴────────────┴───────────┴───────────┴─────────────────────┴───┘

┌────────cnt─┬───────uniq─┬─uniqError─┬─uniqTheta─┬──────────ThetaError─┬─g─┐
│ 1000000000 │ 1001803777 │ 0.1803777 │ 995807422 │ 0.41925779999999996 │ 1 │
└────────────┴────────────┴───────────┴───────────┴─────────────────────┴───┘