> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-home-button.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> 计算加权算术平均值。

# avgWeighted

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

引入版本：v20.1.0

计算[加权算术平均值](https://en.wikipedia.org/wiki/Weighted_arithmetic_mean)。

**语法**

```sql theme={null}
avgWeighted(x, weight)
```

**参数**

* `x` — 值。[`(U)Int*`](/zh/reference/data-types/int-uint) 或 [`Float*`](/zh/reference/data-types/float)
* `weight` — 各值的权重。[`(U)Int*`](/zh/reference/data-types/int-uint) 或 [`Float*`](/zh/reference/data-types/float)

**返回值**

如果所有权重都等于 0，或者提供的 `weight` 参数为空，则返回 `NaN`；否则返回加权平均值。[`Float64`](/zh/reference/data-types/float)

**示例**

**使用示例**

```sql title=Query theme={null}
SELECT avgWeighted(x, w)
FROM VALUES('x Int8, w Int8', (4, 1), (1, 0), (10, 2))
```

```response title=Response theme={null}
┌─avgWeighted(x, w)─┐
│                 8 │
└───────────────────┘
```

**混合整数和浮点数权重**

```sql title=Query theme={null}
SELECT avgWeighted(x, w)
FROM VALUES('x Int8, w Float64', (4, 1), (1, 0), (10, 2))
```

```response title=Response theme={null}
┌─avgWeighted(x, w)─┐
│                 8 │
└───────────────────┘
```

**当所有权重都为零时，返回 NaN**

```sql title=Query theme={null}
SELECT avgWeighted(x, w)
FROM VALUES('x Int8, w Int8', (0, 0), (1, 0), (10, 0))
```

```response title=Response theme={null}
┌─avgWeighted(x, w)─┐
│               nan │
└───────────────────┘
```

**空表会返回 NaN**

```sql title=Query theme={null}
CREATE TABLE test (t UInt8) ENGINE = Memory;
SELECT avgWeighted(t, t) FROM test
```

```response title=Response theme={null}
┌─avgWeighted(t, t)─┐
│               nan │
└───────────────────┘
```