uniqTheta 函数

uniqTheta 函数用于对两个 uniqThetaSketch 对象执行集合操作计算，例如 ∪ / ∩ / ×（并集/交集/非），返回一个包含结果的新 uniqThetaSketch 对象。

uniqThetaSketch 对象由聚合函数 uniqTheta 与 -State 构建。

UniqThetaSketch 是一种近似值集的存储数据结构。有关 RoaringBitmap 的更多信息，请参阅：Theta Sketch Framework.

uniqThetaUnion

两个 uniqThetaSketch 对象执行并集计算（集合操作 ∪），结果是一个新的 uniqThetaSketch。

uniqThetaUnion(uniqThetaSketch,uniqThetaSketch)

参数

• uniqThetaSketch – uniqThetaSketch 对象。

示例

select finalizeAggregation(uniqThetaUnion(a, b)) as a_union_b, finalizeAggregation(a) as a_cardinality, finalizeAggregation(b) as b_cardinality
from
(select arrayReduce('uniqThetaState',[1,2]) as a, arrayReduce('uniqThetaState',[2,3,4]) as b );

┌─a_union_b─┬─a_cardinality─┬─b_cardinality─┐
│         4 │             2 │             3 │
└───────────┴───────────────┴───────────────┘

uniqThetaIntersect

两个 uniqThetaSketch 对象执行交集计算（集合操作 ∩），结果是一个新的 uniqThetaSketch。

uniqThetaIntersect(uniqThetaSketch,uniqThetaSketch)

参数

• uniqThetaSketch – uniqThetaSketch 对象。

示例

select finalizeAggregation(uniqThetaIntersect(a, b)) as a_intersect_b, finalizeAggregation(a) as a_cardinality, finalizeAggregation(b) as b_cardinality
from
(select arrayReduce('uniqThetaState',[1,2]) as a, arrayReduce('uniqThetaState',[2,3,4]) as b );

┌─a_intersect_b─┬─a_cardinality─┬─b_cardinality─┐
│             1 │             2 │             3 │
└───────────────┴───────────────┴───────────────┘

uniqThetaNot

两个 uniqThetaSketch 对象执行 a_not_b 计算（集合操作 ×），结果是一个新的 uniqThetaSketch。

uniqThetaNot(uniqThetaSketch,uniqThetaSketch)

参数

• uniqThetaSketch – uniqThetaSketch 对象。

示例

select finalizeAggregation(uniqThetaNot(a, b)) as a_not_b, finalizeAggregation(a) as a_cardinality, finalizeAggregation(b) as b_cardinality
from
(select arrayReduce('uniqThetaState',[2,3,4]) as a, arrayReduce('uniqThetaState',[1,2]) as b );

┌─a_not_b─┬─a_cardinality─┬─b_cardinality─┐
│       2 │             3 │             2 │
└─────────┴───────────────┴───────────────┘

另请参阅

• uniqThetaSketch