`logTimeMin` SimpleAggregateFunction(min, Int64),`logTimeMax` SimpleAggregateFunction(max, Int64),`dltag` AggregateFunction(groupUniqArray, String),`uri` AggregateFunction(groupUniqArray, String),`errno` AggregateFunction(groupUniqArray, String),`odinLeaf` SimpleAggregateFunction(any, String),`extrac...
SimpleAggregateFunction：类似于AggregateFunction类型，支持更多的聚合函数，且无需应用xx-Merge和xx-State函数来得到值。不常用的（我觉得）：Decimal：P-精度。有效范围：[1:76]，决定可以有多少个十进制数字（包括分数）。S-规模。有效范围：[0：P]，决定数字的小数部分中包含的小数位数。FixedString(N)：顾名思...
min、max、sum、avg 计算每组数据的最小值、最大值、总和、平均值 SELECT min(amount), max(amount), sum(amount), avg(amount) FROM sales_data GROUP BY product, channel; ┌─min(amount)─┬─max(amount)─┬─sum(amount)─┬────────avg(amount)─┐ │ 547 │ 2788 │ 248175 │ 16...
SELECT arrayReduce('max', [1,2,3]) AS minNum,--最大值 3 arrayReduce('min', [1,2,3]) AS maxNum,--最小值 1 arrayReduce('sum', [1,2,3]) AS sumNum;--求和 6 -- 十三、 字符串查分合并函数 --->>> 字符串拆分合并函数 -- 1.splitByChar(separator, s) 将字符串以‘separator...
versionAggregateFunction(max, DateTime64), col1AggregateFunction(argMaxIf, Int32, DateTime64, UInt8), col2AggregateFunction(argMaxIf, String, DateTime64, UInt8), col3AggregateFunction(argMaxIf, DateTime, DateTime64, UInt8)) ENGINE = AggregatingMergeTree ...
ack_user SimpleAggregateFunction(max, LowCardinality(String)) Engine = AggregatingMergeTree() ORDER BY (tenant_id, timestamp, alert_id); 由于原始数据是随机的,因此我们将使用“alerts”中的现有数据填充新表。我们将像之前一样分两次插入,一次是未确认的报警,另一次是已确认的报警: ...
Sign operations在某些计算场景并不适合,比如min、max、quantile等其他场景; 额外的写入放大:当每个对象的平均更新次数为个位数时,更适合使用。 针对Incremental log方式的写入方案存储开销问题,clickhouse提供了CollapsingMergeTree,使用CollapsingMergeTree,“删除”行和旧的“删除”行将在合并过程中折叠。但是,注意这个引擎,...
1.IAggregateFunction接口梳理 话不多说,直接上代码,笔者这里会将所有聚合函数的核心接口代码全部列出,一一梳理各个部分: 构造函数 IAggregateFunction(constDataTypes& argument_types_,constArray& parameters_) :argument_types(argument_types_),parameters(parameters_) {} ...
CREATE TABLE weather_results(city String,max AggregateFunction(max, Decimal(8, 1)),min AggregateFunction(min, Decimal(8, 1)),avg AggregateFunction(avg, Decimal(8, 1))) ENGINE = AggregatingMergeTree ORDER BY tuple() CREATE MATERIALIZED VIEW weather_mv TO weather_resultsAS SELECT city, maxState...
CREATETABLEweather_results(cityString,maxAggregateFunction(max,Decimal(8,1)),minAggregateFunction(min,Decimal(8,1)),avgAggregateFunction(avg,Decimal(8,1)))ENGINE= AggregatingMergeTreeORDERBYtuple CREATEMATERIALIZEDVIEWweather_mvTOweather_resultsASSELECTcity, maxState(temperature)asmax, minState(temperature...