diff --git a/docs/zh/sql-reference/aggregate-functions/reference/quantile.md b/docs/zh/sql-reference/aggregate-functions/reference/quantile.md index 77f858a1735..57369130f9b 100644 --- a/docs/zh/sql-reference/aggregate-functions/reference/quantile.md +++ b/docs/zh/sql-reference/aggregate-functions/reference/quantile.md @@ -4,38 +4,37 @@ toc_priority: 200 # quantile {#quantile} -Computes an approximate [quantile](https://en.wikipedia.org/wiki/Quantile) of a numeric data sequence. +计算数字序列的近似[分位数](https://en.wikipedia.org/wiki/Quantile)。 +此函数应用[水塘抽样][reservoir sampling] (https://en.wikipedia.org/wiki/Reservoir_sampling),使用高达8192的水塘大小和随机数发生器采样。 +结果是不确定的。要获得精确的分位数,使用 [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexact) 函数。 +当在一个查询中使用多个不同层次的 `quantile*` 时,内部状态不会被组合(即查询的工作效率低于组合情况)。在这种情况下,使用 [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) 函数。 -This function applies [reservoir sampling](https://en.wikipedia.org/wiki/Reservoir_sampling) with a reservoir size up to 8192 and a random number generator for sampling. The result is non-deterministic. To get an exact quantile, use the [quantileExact](../../../sql-reference/aggregate-functions/reference/quantileexact.md#quantileexact) function. - -When using multiple `quantile*` functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles) function. - -**Syntax** +**语法** ``` sql quantile(level)(expr) ``` -Alias: `median`. +别名: `median`。 -**Parameters** +**参数** - `level` — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `[0.01, 0.99]`. Default value: 0.5. At `level=0.5` the function calculates [median](https://en.wikipedia.org/wiki/Median). -- `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) or [DateTime](../../../sql-reference/data-types/datetime.md). +- `expr` — Expression over the column values resulting in numeric [data types](../../../sql-reference/data-types/index.md#data_types), [Date](../../../sql-reference/data-types/date.md) 或 [DateTime](../../../sql-reference/data-types/datetime.md). -**Returned value** +**返回值** -- Approximate quantile of the specified level. +- 指定层次的分位数。 -Type: +类型: -- [Float64](../../../sql-reference/data-types/float.md) for numeric data type input. -- [Date](../../../sql-reference/data-types/date.md) if input values have the `Date` type. -- [DateTime](../../../sql-reference/data-types/datetime.md) if input values have the `DateTime` type. +- [Float64](../../../sql-reference/data-types/float.md) 用于数字数据类型输入。 +- [Date](../../../sql-reference/data-types/date.md) 如果输入值是 `Date` 类型。 +- [DateTime](../../../sql-reference/data-types/datetime.md) 如果输入值是 `DateTime` 类型。 -**Example** +**示例** -Input table: +输入表: ``` text ┌─val─┐ @@ -46,13 +45,13 @@ Input table: └─────┘ ``` -Query: +查询: ``` sql SELECT quantile(val) FROM t ``` -Result: +结果: ``` text ┌─quantile(val)─┐ @@ -60,7 +59,7 @@ Result: └───────────────┘ ``` -**See Also** +**参见** - [median](../../../sql-reference/aggregate-functions/reference/median.md#median) - [quantiles](../../../sql-reference/aggregate-functions/reference/quantiles.md#quantiles)