> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

> 结果等于 varSamp 的平方根。不同的是，此函数采用数值稳定算法。

# stddevSampStable

<div id="stddevSampStable">
  ## stddevSampStable
</div>

Introduced in：v1.1.0

其结果等于 [varSamp](/zh/reference/functions/aggregate-functions/varSamp) 的平方根。与 [stddevSamp](/zh/reference/functions/aggregate-functions/stddevSamp) 不同，此函数采用数值稳定的算法。虽然运行较慢，但计算误差更低。

**Syntax**

```sql theme={null}
stddevSampStable(x)
```

**参数**

* `x` — 用于计算样本方差平方根的值。[`(U)Int*`](/zh/reference/data-types/int-uint) 或 [`Float*`](/zh/reference/data-types/float) 或 [`Decimal*`](/zh/reference/data-types/decimal)

**返回值**

返回 `x` 的样本方差平方根。[`Float64`](/zh/reference/data-types/float)

**示例**

**基本用法**

```sql title=Query theme={null}
DROP TABLE IF EXISTS test_data;
CREATE TABLE test_data
(
    population UInt8,
)
ENGINE = Log;

INSERT INTO test_data VALUES (3),(3),(3),(4),(4),(5),(5),(7),(11),(15);

SELECT
    stddevSampStable(population)
FROM test_data;
```

```response title=Response theme={null}
┌─stddevSampStable(population)─┐
│                            4 │
└──────────────────────────────┘
```