mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-02 04:22:03 +00:00
80 lines
2.6 KiB
Markdown
80 lines
2.6 KiB
Markdown
---
|
|
slug: /en/sql-reference/aggregate-functions/reference/grouparraymovingavg
|
|
sidebar_position: 114
|
|
---
|
|
|
|
# groupArrayMovingAvg
|
|
|
|
Calculates the moving average of input values.
|
|
|
|
``` sql
|
|
groupArrayMovingAvg(numbers_for_summing)
|
|
groupArrayMovingAvg(window_size)(numbers_for_summing)
|
|
```
|
|
|
|
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.
|
|
|
|
**Arguments**
|
|
|
|
- `numbers_for_summing` — [Expression](../../../sql-reference/syntax.md#syntax-expressions) resulting in a numeric data type value.
|
|
- `window_size` — Size of the calculation window.
|
|
|
|
**Returned values**
|
|
|
|
- Array of the same size and type as the input data.
|
|
|
|
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.
|
|
|
|
**Example**
|
|
|
|
The sample table `b`:
|
|
|
|
``` sql
|
|
CREATE TABLE t
|
|
(
|
|
`int` UInt8,
|
|
`float` Float32,
|
|
`dec` Decimal32(2)
|
|
)
|
|
ENGINE = TinyLog
|
|
```
|
|
|
|
``` text
|
|
┌─int─┬─float─┬──dec─┐
|
|
│ 1 │ 1.1 │ 1.10 │
|
|
│ 2 │ 2.2 │ 2.20 │
|
|
│ 4 │ 4.4 │ 4.40 │
|
|
│ 7 │ 7.77 │ 7.77 │
|
|
└─────┴───────┴──────┘
|
|
```
|
|
|
|
The queries:
|
|
|
|
``` sql
|
|
SELECT
|
|
groupArrayMovingAvg(int) AS I,
|
|
groupArrayMovingAvg(float) AS F,
|
|
groupArrayMovingAvg(dec) AS D
|
|
FROM t
|
|
```
|
|
|
|
``` text
|
|
┌─I─────────┬─F───────────────────────────────────┬─D─────────────────────┐
|
|
│ [0,0,1,3] │ [0.275,0.82500005,1.9250001,3.8675] │ [0.27,0.82,1.92,3.86] │
|
|
└───────────┴─────────────────────────────────────┴───────────────────────┘
|
|
```
|
|
|
|
``` sql
|
|
SELECT
|
|
groupArrayMovingAvg(2)(int) AS I,
|
|
groupArrayMovingAvg(2)(float) AS F,
|
|
groupArrayMovingAvg(2)(dec) AS D
|
|
FROM t
|
|
```
|
|
|
|
``` text
|
|
┌─I─────────┬─F────────────────────────────────┬─D─────────────────────┐
|
|
│ [0,1,3,5] │ [0.55,1.6500001,3.3000002,6.085] │ [0.55,1.65,3.30,6.08] │
|
|
└───────────┴──────────────────────────────────┴───────────────────────┘
|
|
```
|