在使用Presto中实现collect_set函数之前,我们首先需要了解一下Presto和collect_set函数的基本概念。 Presto是一个高效的分布式SQL查询引擎,它可以快速地查询大规模的数据。而collect_set函数是Presto中用于聚合数据的函数,它可以将一个列中的数据进行去重和聚合,最终返回一个不重复的值集合。 接下来,我们来看一下如何在...
presto collect_set 集合元素重复度 获取集合中重复的元素,背景统计List集合中元素出现的次数,相信大家都做过。举个例子,我们要统计集合中名字重复的次数。List<String>nameLists=Arrays.asList("Lvshen","Lvshen","Zhouzhou","Huamulan","Huamulan","Huamulan");
packageorg.example.calc;importjava.util.*;publicclassCalcByHand{// 定义操作符并区分优先级,*/ 优先级较高publicstaticSet<String>opSet1=newHashSet<>();publicstaticSet<String>opSet2=newHashSet<>();static{opSet1.add("+");opSet1.add("-");opSet2.add("*");opSet2.add("/"); }publicstatic...
...collect_list -> array_agg concat_ws -> array_join collect_set -> array_agg 后 array_distinct去重 行专列 Hive:split拆分成数组...,lateral view explode将数组分开 lateral view explode(split(id_list, ',')) b as oid ; Presto:split拆分成数组,cross...join unnest将数组分开,要注意一下...
1importcom.facebook.presto.spi.Plugin;23importcom.google.common.collect.ImmutableSet;467importjava.util.Set;89publicclassPrestoFunctionsPluginimplementsPlugin {10@Override11publicSet<Class<?>>getFunctions() {12returnImmutableSet.<Class<?>>builder()13.add(PvFlowStatsAggregation.class)14.add(AvgAggregatio...
--prestoselectarray_join(array_distinct(array_agg(name)),',')--hiveselectconcat_ws(',',collect_set(cast(nameasstring))) 时间差计算 Presto:selectdate_diff('day',cast('2020-07-23 15:01:13'astimestamp),cast('2020-07-24 11:42:58'astimestamp)) ...
empty(); } Set<String> undefinedColumns = Sets.difference( ImmutableSet.copyOf(distributeColumns), tableMetadata.getColumns().stream() .map(ColumnMetadata::getName) .collect(toSet())); if (!undefinedColumns.isEmpty()) { throw new PrestoException(INVALID_TABLE_PROPERTY, "Distribute columns not...
packagecom.lansonjy.prestocode;importcom.facebook.presto.spi.Plugin;importcom.google.common.collect.ImmutableSet;importjava.util.Set;//Presto 注册自定义函数的类,此类需要继承Plugin接口publicclassMyFunctionsPluginimplementsPlugin{@OverridepublicSet<Class<?>>getFunctions(){returnImmutableSet.<Class<?>>builder...
package com.example.presto; import com.facebook.presto.spi.Plugin; import com.google.common.collect.ImmutableSet; import java.util.Set; public class UpperCasePlugin implements Plugin { @Override public Set<Class<?>> getFunctions() { return ImmutableSet.<Class<?>>bu...
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