approx_distinct
approx_distinct
calculates an approximate count of the number of distinct values. It provides an approximation to count
(distinct) but is much faster. approx_distinct
should produce a standard error of 2.3%, the standard deviation of the error distribution over all input sets. approx_distinct
does not guarantee a bound on the error for any specific input set.
Parameter | Type | Description |
---|---|---|
| any | the values to be counted |
Returns: any
Example
Query:
PREFIX : <https://ddw-doccorp.linked.data.world/d/sparql-aggregation-sample-queries/> PREFIX agg: <http://data.world/function/aggregate#> SELECT (agg:approx_median(?foo) AS ?approx_median) { [ :col-aggregations-foo ?foo ] }
Result:
approx_distinct |
---|
5 |