TypedAggregateExpression Expression¶

TypedAggregateExpression is the <> for spark-sql-Expression-AggregateFunction.md[AggregateFunction] expressions that...FIXME

[[contract]] [source, scala]

package org.apache.spark.sql.execution.aggregate

trait TypedAggregateExpression extends AggregateFunction { // only required methods that have no implementation def aggregator: Aggregator[Any, Any, Any] def inputClass: Option[Class[]] def inputDeserializer: Option[Expression] def inputSchema: Option[StructType] def withInputInfo(deser: Expression, cls: Class[], schema: StructType): TypedAggregateExpression }

TypedAggregateExpression is used when:

• TypedColumn is requested to withInputType (for Dataset.select, KeyValueGroupedDataset.agg and RelationalGroupedDataset.agg operators)

• Column is requested to generateAlias and named (for Dataset.select and KeyValueGroupedDataset.agg operators)

• RelationalGroupedDataset is requested to alias (when RelationalGroupedDataset is requested to create a DataFrame from aggregate expressions)

.TypedAggregateExpression Contract [cols="1,2",options="header",width="100%"] |=== | Method | Description

| [[aggregator]] aggregator | Aggregator

| [[inputClass]] inputClass | Used when...FIXME

| [[inputDeserializer]] inputDeserializer | Used when...FIXME

| [[inputSchema]] inputSchema | Used when...FIXME

| [[withInputInfo]] withInputInfo | Used when...FIXME |===

[[implementations]] .TypedAggregateExpressions [cols="1,2",options="header",width="100%"] |=== | Aggregator | Description

=== [[apply]] Creating TypedAggregateExpression -- apply Factory Method

[source, scala]¶

applyBUF : Encoder, OUT : Encoder: TypedAggregateExpression

apply...FIXME

apply is used when Aggregator is requested to convert itself to a TypedColumn.