io.druid.sql.calcite.aggregation

Interface SqlAggregator

All Known Implementing Classes:

ApproxCountDistinctSqlAggregator, AvgSqlAggregator, CountSqlAggregator, MaxSqlAggregator, MinSqlAggregator, QuantileSqlAggregator, SumSqlAggregator, SumZeroSqlAggregator

public interface SqlAggregator

Bridge between Druid and SQL aggregators.

Method Summary

Modifier and Type	Method and Description
org.apache.calcite.sql.SqlAggFunction	calciteFunction() Returns the SQL operator corresponding to this aggregation function.
Aggregation	toDruidAggregation(PlannerContext plannerContext, RowSignature rowSignature, org.apache.calcite.rex.RexBuilder rexBuilder, String name, org.apache.calcite.rel.core.AggregateCall aggregateCall, org.apache.calcite.rel.core.Project project, List<Aggregation> existingAggregations) Returns a Druid Aggregation corresponding to a SQL AggregateCall.

Method Detail

calciteFunction

org.apache.calcite.sql.SqlAggFunction calciteFunction()

Returns the SQL operator corresponding to this aggregation function. Should be a singleton.

Returns:

operator

toDruidAggregation

@Nullable
Aggregation toDruidAggregation(PlannerContext plannerContext,
                                         RowSignature rowSignature,
                                         org.apache.calcite.rex.RexBuilder rexBuilder,
                                         String name,
                                         org.apache.calcite.rel.core.AggregateCall aggregateCall,
                                         org.apache.calcite.rel.core.Project project,
                                         List<Aggregation> existingAggregations)

Returns a Druid Aggregation corresponding to a SQL AggregateCall. This method should ignore filters; they will be applied to your aggregator in a later step.

Parameters:

plannerContext - SQL planner context

rowSignature - signature of the rows being aggregated

rexBuilder - a rexBuilder, in case you need one

name - desired output name of the aggregation

aggregateCall - aggregate call object

project - project that should be applied before aggregation; may be null

existingAggregations - existing aggregations for this query; useful for re-using aggregations. May be safely ignored if you do not want to re-use existing aggregations.

Returns:

aggregation, or null if the call cannot be translated