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79 lines
2.5 KiB
Markdown
79 lines
2.5 KiB
Markdown
---
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toc_priority: 114
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---
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# groupArrayMovingAvg {#agg_function-grouparraymovingavg}
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Calculates the moving average of input values.
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``` sql
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groupArrayMovingAvg(numbers_for_summing)
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groupArrayMovingAvg(window_size)(numbers_for_summing)
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```
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The function can take the window size as a parameter. If left unspecified, the function takes the window size equal to the number of rows in the column.
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**Arguments**
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- `numbers_for_summing` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in a numeric data type value.
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- `window_size` — Size of the calculation window.
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**Returned values**
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- Array of the same size and type as the input data.
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The function uses [rounding towards zero](https://en.wikipedia.org/wiki/Rounding#Rounding_towards_zero). It truncates the decimal places insignificant for the resulting data type.
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**Example**
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The sample table `b`:
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``` sql
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CREATE TABLE t
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(
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`int` UInt8,
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`float` Float32,
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`dec` Decimal32(2)
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)
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ENGINE = TinyLog
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```
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``` text
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┌─int─┬─float─┬──dec─┐
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│ 1 │ 1.1 │ 1.10 │
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│ 2 │ 2.2 │ 2.20 │
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│ 4 │ 4.4 │ 4.40 │
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│ 7 │ 7.77 │ 7.77 │
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└─────┴───────┴──────┘
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```
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The queries:
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``` sql
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SELECT
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groupArrayMovingAvg(int) AS I,
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groupArrayMovingAvg(float) AS F,
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groupArrayMovingAvg(dec) AS D
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FROM t
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```
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``` text
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┌─I─────────┬─F───────────────────────────────────┬─D─────────────────────┐
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│ [0,0,1,3] │ [0.275,0.82500005,1.9250001,3.8675] │ [0.27,0.82,1.92,3.86] │
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└───────────┴─────────────────────────────────────┴───────────────────────┘
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```
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``` sql
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SELECT
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groupArrayMovingAvg(2)(int) AS I,
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groupArrayMovingAvg(2)(float) AS F,
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groupArrayMovingAvg(2)(dec) AS D
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FROM t
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```
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``` text
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┌─I─────────┬─F────────────────────────────────┬─D─────────────────────┐
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│ [0,1,3,5] │ [0.55,1.6500001,3.3000002,6.085] │ [0.55,1.65,3.30,6.08] │
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└───────────┴──────────────────────────────────┴───────────────────────┘
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```
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