ClickHouse/docs/en/sql-reference/aggregate-functions/reference/grouparraymovingavg.md
Ivan Blinkov 7170f3c534
[docs] split aggregate function and system table references (#11742)
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---
toc_priority: 114
---
# groupArrayMovingAvg {#agg_function-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.
**Parameters**
- `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] │
└───────────┴──────────────────────────────────┴───────────────────────┘
```