Package org.apache.druid.sql.calcite.aggregation

Class Aggregations

java.lang.Object

org.apache.druid.sql.calcite.aggregation.Aggregations

public class Aggregations
extends Object

Method Summary

Modifier and Type	Method	Description
static List<DruidExpression>	getArgumentsForSimpleAggregator(PlannerContext plannerContext, org.apache.calcite.rel.core.AggregateCall call, InputAccessor inputAccessor)	Get Druid expressions that correspond to "simple" aggregator inputs.
static DruidExpression	toDruidExpressionForNumericAggregator(PlannerContext plannerContext, RowSignature rowSignature, org.apache.calcite.rex.RexNode rexNode)	Translate a Calcite RexNode to a Druid expression for the aggregators that require numeric type inputs.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

getArgumentsForSimpleAggregator

@Nullable
public static List<DruidExpression> getArgumentsForSimpleAggregator(PlannerContext plannerContext,
 org.apache.calcite.rel.core.AggregateCall call,
 InputAccessor inputAccessor)

Get Druid expressions that correspond to "simple" aggregator inputs. This is used by standard sum/min/max aggregators, which have the following properties: 1) They can take direct field accesses or expressions as inputs. 2) They cannot implicitly cast strings to numbers when using a direct field access.

Parameters:

plannerContext - SQL planner context

call - aggregate call object

inputAccessor - gives access to input fields and schema

Returns:

list of expressions corresponding to aggregator arguments, or null if any cannot be translated

toDruidExpressionForNumericAggregator

public static DruidExpression toDruidExpressionForNumericAggregator(PlannerContext plannerContext,
 RowSignature rowSignature,
 org.apache.calcite.rex.RexNode rexNode)

Translate a Calcite RexNode to a Druid expression for the aggregators that require numeric type inputs. The returned expression can keep an explicit cast from strings to numbers when the column consumed by the expression is the string type. Consider using Expressions.toDruidExpression(PlannerContext, RowSignature, RexNode) for projections or the aggregators that don't require numeric inputs.

Parameters:

plannerContext - SQL planner context

rowSignature - signature of the rows to be extracted from

rexNode - expression meant to be applied on top of the rows

Returns:

DruidExpression referring to fields in rowOrder, or null if not possible to translate