198、Spark 2.0之Dataset开发详解-聚合函数:collect_list、collect_set
collect_list和collect_set,都用于将同一个分组内的指定字段的值串起来,变成一个数组常用于行转列比如说depId=1,employee=leodepId=1,employee=jackdepId=1,employees=[leo,jack]代码objectAggregateFunction{caseclassEmployee(name:String,age:Long,depId