clickhouse select 带有移动过滤器的请求

Question

需要一些帮助）我有一个简单的请求：

    SELECT uniq(DeviceId)
    from events
    where EventDateTime between '2020-12-28 00:00:00' and '2020-12-28 23:59:59'

现在，我需要轮班一小时才能找到相同的结果：

    SELECT uniq(DeviceId)
    from events
    where EventDateTime between '2020-12-27 00:23:00' and '2020-12-28 22:59:59'

还有一小时：

    SELECT uniq(DeviceId)
    from events
    where EventDateTime between '2020-12-27 00:22:00' and '2020-12-28 21:59:59'

所以，24 小时内我需要 24 个请求 - 有没有办法在一个请求中完成此操作？

预期结果：

'2020-12-28 00:00:00' - '2020-12-28 23:59:59', 'uniqValue1'
'2020-12-27 00:23:00' - '2020-12-28 22:59:59', 'uniqValue2' 
'2020-12-27 00:22:00' - '2020-12-28 21:59:59', 'uniqValue3'
... 
'2020-12-27 00:00:00' - '2020-12-27 23:59:59, 'uniqValue24'

Answer 1

已更新：

WITH 5 AS steps
SELECT result.2 EventDateTime, result.1 UniqDeviceId
FROM
(
    SELECT
        groupArray(hour) AS hour_arr,    
        groupArray(uniqDeviceIdState) AS state_arr,
        arrayReduceInRanges('uniqMerge', arrayMap(x -> (x, length(state_arr)), range(1, 1 + steps)), state_arr) AS calculated_uniq_metrics,
        arrayMap((x, i) -> (x, hour_arr[i]), calculated_uniq_metrics, arrayEnumerate(calculated_uniq_metrics)) metric_hour_arr,
        arrayJoin(metric_hour_arr) result
    FROM
    (
        SELECT
            toStartOfHour(EventDateTime) AS hour,
            uniqState(DeviceId) AS uniqDeviceIdState
        FROM
        (
            /* Emulate the test dataset. */
            SELECT
                addHours(toDate('2020-05-05'), hour) AS EventDateTime ,
                arrayJoin(DeviceIds) AS DeviceId
            FROM
            (
                SELECT
                    number % 48 AS hour,
                    groupArray(number) AS DeviceIds
                FROM numbers(96)
                GROUP BY hour
            )
        )
        WHERE EventDateTime between '2020-05-05 00:00:00' and '2020-05-07 23:59:59'
        GROUP BY hour
        ORDER BY hour ASC
    )
)

/*
┌───────EventDateTime─┬─UniqDeviceId─┐
│ 2020-05-05 00:00:00 │           96 │
│ 2020-05-05 01:00:00 │           94 │
│ 2020-05-05 02:00:00 │           92 │
│ 2020-05-05 03:00:00 │           90 │
│ 2020-05-05 04:00:00 │           88 │
└─────────────────────┴──────────────┘
*/

考虑使用分组和 toStartOfHour-函数：

SELECT toStartOfHour(EventDateTime) startOfHour, uniq(DeviceId)
from events
where EventDateTime between '2020-12-28 00:00:00' and '2020-12-28 23:59:59'
group by startOfHour
order by startOfHour

clickhouse select 带有移动过滤器的请求

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