sumMappedArrays

Totals one or more value arrays according to the keys specified in the key array.

Totals one or more value arrays according to the keys specified in the key array. Returns a tuple of arrays: keys in sorted order, followed by values summed for the corresponding keys without overflow.

:::note

Passing a tuple of keys and value arrays is identical to passing an array of keys and an array of values.
The number of elements in key and all value arrays must be the same for each row that is totaled. :::

Syntax

sumMappedArrays(key, value1 [, value2, ...])
sumMappedArrays(Tuple(key, value1 [, value2, ...]))

Arguments

key — Array of keys. Array
value1, value2, ... — Arrays of values to sum for each key. Array

Returned value

Returns a tuple of arrays: the first array contains keys in sorted order, followed by arrays containing values summed for the corresponding keys. Tuple

Examples

Basic usage with Nested type

CREATE TABLE sum_map(
    date Date,
    timeslot DateTime,
    statusMap Nested(
        status UInt16,
        requests UInt64
    ),
    statusMapTuple Tuple(Array(Int32), Array(Int32))
) ENGINE = Memory;

INSERT INTO sum_map VALUES
    ('2000-01-01', '2000-01-01 00:00:00', [1, 2, 3], [10, 10, 10], ([1, 2, 3], [10, 10, 10])),
    ('2000-01-01', '2000-01-01 00:00:00', [3, 4, 5], [10, 10, 10], ([3, 4, 5], [10, 10, 10])),
    ('2000-01-01', '2000-01-01 00:01:00', [4, 5, 6], [10, 10, 10], ([4, 5, 6], [10, 10, 10])),
    ('2000-01-01', '2000-01-01 00:01:00', [6, 7, 8], [10, 10, 10], ([6, 7, 8], [10, 10, 10]));

SELECT
    timeslot,
    sumMappedArrays(statusMap.status, statusMap.requests),
    sumMappedArrays(statusMapTuple)
FROM sum_map
GROUP BY timeslot;

┌────────────timeslot─┬─sumMappedArrays(statusMap.status, statusMap.requests)─┬─sumMappedArrays(statusMapTuple)─────────┐
│ 2000-01-01 00:00:00 │ ([1,2,3,4,5],[10,10,20,10,10])                        │ ([1,2,3,4,5],[10,10,20,10,10])          │
│ 2000-01-01 00:01:00 │ ([4,5,6,7,8],[10,10,20,10,10])                        │ ([4,5,6,7,8],[10,10,20,10,10])          │
└─────────────────────┴───────────────────────────────────────────────────────┴─────────────────────────────────────────┘

Multiple value arrays example

CREATE TABLE multi_metrics(
    date Date,
    browser_metrics Nested(
        browser String,
        impressions UInt32,
        clicks UInt32
    )
)
ENGINE = Memory;

INSERT INTO multi_metrics VALUES
    ('2000-01-01', ['Firefox', 'Chrome'], [100, 200], [10, 25]),
    ('2000-01-01', ['Chrome', 'Safari'], [150, 50], [20, 5]),
    ('2000-01-01', ['Firefox', 'Edge'], [80, 40], [8, 4]);

SELECT
    sumMappedArrays(browser_metrics.browser, browser_metrics.impressions, browser_metrics.clicks) AS result
FROM multi_metrics;

┌─result────────────────────────────────────────────────────────────────────────┐
│ (['Chrome', 'Edge', 'Firefox', 'Safari'], [350, 40, 180, 50], [45, 4, 18, 5]) │
└───────────────────────────────────────────────────────────────────────────────┘
-- In this example:
-- The result tuple contains three arrays
-- First array: keys (browser names) in sorted order
-- Second array: total impressions for each browser
-- Third array: total clicks for each browser

Introduced in version 1.1.