select Clickhouse嵌套 map：与总数一起指定

select - Clickhouse嵌套 map：与总数一起指定

发布于 2020-03-28 23:26:04

带有嵌套 map的Clickhouse表：

CREATE TABLE IF NOT EXISTS Test.NestedTest2
(
    -- slices
    idx1 UInt8, -- just some index 1
    idx2 UInt8, -- just some index 2

    -- metrics
    totalCnt UInt64,  -- total http response count
    codeMap Nested(
        key UInt16,   -- http response code
        value UInt64  -- http response count
    )

) Engine MergeTree()
PARTITION BY (idx1)
ORDER BY (idx1, idx2)


INSERT INTO Test.NestedTest2 (idx1, idx2, totalCnt, codeMap.key, codeMap.value) 
VALUES 
    (1, 1, 5, array(200), array(5))
    (1, 1, 5, array(204), array(5))
    (1, 1, 15, array(404, 502), array(5, 10))
    (1, 2, 45, array(404, 502), array(20, 25))
    (2, 1, 20, array(404, 502, 200), array(5, 5, 10))

此处totalCnt仅作为示例。它可能与总价值相关，例如memoryUsage。

我需要在同一选择的总响应中获取特定的代码响应计数：

-- where idx1 = 1
/*
┌─code─┬─count─┬─totalCnt─┐
│  200 │     5 │       70 │
│  204 │     5 │       70 │
│  404 │    25 │       70 │
│  502 │    35 │       70 │
└──────┴───────┴──────────┘
*/

Denis Zhuravlev 2020-02-01 04:08

SELECT
    idx1,
    (arrayJoin(arrayMap((x, y) -> (x, y), (sumMap(codeMap.key, codeMap.value) AS a).1, a.2)) AS arr).1 AS code,
    arr.2 AS cnt,
    sum(totalCnt) AS total
FROM Test.NestedTest2
WHERE idx1 = 1
GROUP BY idx1

┌─idx1─┬─code─┬─cnt─┬─total─┐
│    1 │  200 │   5 │    70 │
│    1 │  204 │   5 │    70 │
│    1 │  404 │  25 │    70 │
│    1 │  502 │  35 │    70 │
└──────┴──────┴─────┴───────┘

顺便说一句，你可以计算出total从codeMap.value-arrayReduce('sum', groupArrayArray

SELECT
    idx1,
    (arrayJoin(arrayMap((x, y) -> (x, y), (sumMap(codeMap.key, codeMap.value) AS a).1, a.2)) AS arr).1 AS code,
    arr.2 AS cnt,
    arrayReduce('sum', groupArrayArray(codeMap.value)) AS total
FROM Test.NestedTest2
WHERE idx1 = 1
GROUP BY idx1

┌─idx1─┬─code─┬─cnt─┬─total─┐
│    1 │  200 │   5 │    70 │
│    1 │  204 │   5 │    70 │
│    1 │  404 │  25 │    70 │
│    1 │  502 │  35 │    70 │
└──────┴──────┴─────┴───────┘

select - Clickhouse嵌套 map：与总数一起指定

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