Project: ClickHouse (App Definition and Development / Database)
File: quantileexact.md

slug: /en/sql-reference/aggregate-functions/reference/quantileexact sidebar_position: 202 Exactly computes the of a numeric data sequence. To get exact value, all the passed values are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective. 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 function. Syntax ``` sql quantileExact(level)(expr) ``` Alias: `medianExact`. Arguments `level` Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `. `expr` Expression over the column values resulting in numeric , or . Returned value Quantile of the specified level. Type: for numeric data type input. if input values have the `Date` type. if input values have the `DateTime` type. Example Query: ``` sql SELECT quantileExact(number) FROM numbers(10) ``` Result: ``` text quantileExact(number) 5 ``` Similar to `quantileExact`, this computes the exact of a numeric data sequence. To get the exact value, all the passed values are combined into an array, which is then fully sorted. The sorting complexity is `O(Nlog(N))`, where `N = std::distance(first, last)` comparisons. The return value depends on the quantile level and the number of elements in the selection, i.e. if the level is 0.5, then the function returns the lower median value for an even number of elements and the middle median value for an odd number of elements. Median is calculated similarly to the implementation which is used in python. For all other levels, the element at the index corresponding to the value of `level * sizeofarray` is returned. For example: ``` sql SELECT quantileExactLow(0.1)(number) FROM numbers(10) quantileExactLow(0.1)(number) 1 ``` 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 function. Syntax ``` sql quantileExactLow(level)(expr) ``` Alias: `medianExactLow`. Arguments `level` Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `. `expr` Expression over the column values resulting in numeric , or . Returned value Quantile of the specified level. Type: for numeric data type input. if input values have the `Date` type. if input values have the `DateTime` type. Example Query: ``` sql SELECT quantileExactLow(number) FROM numbers(10) ``` Result: ``` text quantileExactLow(number) 4 ``` Similar to `quantileExact`, this computes the exact of a numeric data sequence. All the passed values are combined into an array, which is then fully sorted, to get the exact value. The sorting complexity is `O(Nlog(N))`, where `N = std::distance(first, last)` comparisons. The return value depends on the quantile level and the number of elements in the selection, i.e. if the level is 0.5, then the function returns the higher median value for an even number of elements and the middle median value for an odd number of

Median is calculated similarly to the implementation which is used in python. For all other levels, the element at the index corresponding to the value of `level * sizeofarray` is returned. This implementation behaves exactly similar to the current `quantileExact` implementation. 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 function. Syntax ``` sql quantileExactHigh(level)(expr) ``` Alias: `medianExactHigh`. Arguments `level` Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a `level` value in the range of `. `expr` Expression over the column values resulting in numeric , or . Returned value Quantile of the specified level. Type: for numeric data type input. if input values have the `Date` type. if input values have the `DateTime` type. Example Query: ``` sql SELECT quantileExactHigh(number) FROM numbers(10) ``` Result: ``` text quantileExactHigh(number) 5 ``` Exactly computes the of a numeric data sequence. To get exact value, all the passed values are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective. This function is equivalent to Excel function, (). When using multiple `quantileExactExclusive` 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 function. Syntax ``` sql quantileExactExclusive(level)(expr) ``` Arguments `expr` Expression over the column values resulting in numeric , or . Parameters `level` Level of quantile. Optional. Possible values: (0, 1) bounds not included. Default value: 0.5. At `level=0.5` the function calculates . . Returned value Quantile of the specified level. Type: for numeric data type input. if input values have the `Date` type. if input values have the `DateTime` type. Example Query: ``` sql CREATE TABLE num AS numbers(1000); SELECT quantileExactExclusive(0.6)(x) FROM (SELECT number AS x FROM num); ``` Result: ``` text quantileExactExclusive(0.6)(x) 599.6 ``` Exactly computes the of a numeric data sequence. To get exact value, all the passed values are combined into an array, which is then partially sorted. Therefore, the function consumes `O(n)` memory, where `n` is a number of values that were passed. However, for a small number of values, the function is very effective. This function is equivalent to Excel function, (). When using multiple `quantileExactInclusive` 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 function. Syntax ``` sql quantileExactInclusive(level)(expr) ``` Arguments `expr` Expression over the column values resulting in numeric , or . Parameters `level` Level of quantile. Optional. Possible values: . . Returned value Quantile of the specified level. Type: for numeric data type input. if input values have the `Date` type. if input values have the `DateTime` type. Example Query: ``` sql CREATE TABLE num AS numbers(1000); SELECT quantileExactInclusive(0.6)(x) FROM (SELECT number AS x FROM num); ``` Result: ``` text quantileExactInclusive(0.6)(x) 599.4 ``` See Also