dcount_hll()dcount_hll()

• 10/29/2020
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根据 hll 结果（已由 hll 或 hll_merge 生成）计算 dcount。Calculates the dcount from hll results (that were generated by hll or hll_merge).

阅读基础算法 (HyperLogLog ) 和估算准确度。Read about the underlying algorithm ( H yper L og L og) and estimation accuracy.

语法Syntax

dcount_hll(Expr)dcount_hll(Expr)

参数Arguments

• Expr：已由 hll 或 hll-merge 生成的表达式Expr : Expression that was generated by hll or hll-merge

返回Returns

Expr 中每个值的非重复计数The distinct count of each value in Expr

示例Examples

StormEvents
| summarize hllRes = hll(DamageProperty) by bin(StartTime,10m)
| summarize hllMerged = hll_merge(hllRes)
| project dcount_hll(hllMerged)