hll_merge()hll_merge()

合并 hll 结果(聚合版 hll_merge() 的标量版本)。Merges hll results (scalar version of the aggregate version hll_merge()).

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

语法Syntax

hll_merge( Expr1, Expr2, ...)hll_merge( Expr1, Expr2, ...)

参数Arguments

  • 包含要合并的 hll 值的列。Columns that have hll values to be merged.

返回Returns

将列 *Exrp1**Expr2*、... *ExprN* 合并为一个 hll 值后的结果。The result for merging the columns *Exrp1*, *Expr2*, ... *ExprN* to one hll value.

示例Examples

range x from 1 to 10 step 1 
| extend y = x + 10
| summarize hll_x = hll(x), hll_y = hll(y)
| project merged = hll_merge(hll_x, hll_y)
| project dcount_hll(merged)
dcount_hll_merged
2020