DeclarativeAggregate -- Unevaluable Aggregate Function Expressions¶

DeclarativeAggregate is an <> of the <> for <> that are unevaluable and use expressions for evaluation.

[[contract]] .DeclarativeAggregate Contract [cols="1m,2",options="header",width="100%"] |=== | Property | Description

| evaluateExpression a| [[evaluateExpression]]

[source, scala]¶

evaluateExpression: Expression¶

The <> that returns the final value for the aggregate function

Used when:

• AggregationIterator is requested for the generateResultProjection

• HashAggregateExec physical operator is requested to doProduceWithoutKeys and generateResultFunction

• AggregateProcessor is created (when WindowExec physical operator is <>)

| initialValues a| [[initialValues]]

[source, scala]¶

initialValues: Seq[Expression]¶

| mergeExpressions a| [[mergeExpressions]]

[source, scala]¶

mergeExpressions: Seq[Expression]¶

| updateExpressions a| [[updateExpressions]]

[source, scala]¶

updateExpressions: Seq[Expression]¶

|===

[[extensions]] .DeclarativeAggregates (Direct Implementations) [cols="1,2",options="header",width="100%"] |=== | DeclarativeAggregate | Description

| <> | [[AggregateWindowFunction]] Contract for declarative window aggregate function expressions

| Average | [[Average]]

| CentralMomentAgg | [[CentralMomentAgg]]

| Corr | [[Corr]]

| Count | [[Count]]

| Covariance | [[Covariance]]

| <> | [[First]]

| Last | [[Last]]

| Max | [[Max]]

| Min | [[Min]]

| <> | [[SimpleTypedAggregateExpression]]

| Sum | [[Sum]] |===