mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-15 19:02:04 +00:00
50 lines
1.2 KiB
Markdown
50 lines
1.2 KiB
Markdown
---
|
|
slug: /en/sql-reference/aggregate-functions/reference/stddevpopstable
|
|
sidebar_position: 189
|
|
---
|
|
|
|
# stddevPopStable
|
|
|
|
The result is equal to the square root of [varPop](../../../sql-reference/aggregate-functions/reference/varpop.md). Unlike [`stddevPop`](../reference/stddevpop.md), this function uses a numerically stable algorithm. It works slower but provides a lower computational error.
|
|
|
|
**Syntax**
|
|
|
|
```sql
|
|
stddevPopStable(x)
|
|
```
|
|
|
|
**Parameters**
|
|
|
|
- `x`: Population of values to find the standard deviation of. [(U)Int*](../../data-types/int-uint.md), [Float*](../../data-types/float.md), [Decimal*](../../data-types/decimal.md).
|
|
|
|
**Returned value**
|
|
|
|
Square root of standard deviation of `x`. [Float64](../../data-types/float.md).
|
|
|
|
**Example**
|
|
|
|
Query:
|
|
|
|
```sql
|
|
DROP TABLE IF EXISTS test_data;
|
|
CREATE TABLE test_data
|
|
(
|
|
population Float64,
|
|
)
|
|
ENGINE = Log;
|
|
|
|
INSERT INTO test_data SELECT randUniform(5.5, 10) FROM numbers(1000000)
|
|
|
|
SELECT
|
|
stddevPopStable(population) AS stddev
|
|
FROM test_data;
|
|
```
|
|
|
|
Result:
|
|
|
|
```response
|
|
┌─────────────stddev─┐
|
|
│ 1.2999977786592576 │
|
|
└────────────────────┘
|
|
```
|