Package org.apache.calcite.sql

Class SqlSplittableAggFunction.SelfSplitter

java.lang.Object

org.apache.calcite.sql.SqlSplittableAggFunction.SelfSplitter

All Implemented Interfaces:

SqlSplittableAggFunction

Enclosing interface:

SqlSplittableAggFunction

public static class SqlSplittableAggFunction.SelfSplitter
extends java.lang.Object
implements SqlSplittableAggFunction

Aggregate function that splits into two applications of itself.

Examples are MIN and MAX.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.sql.SqlSplittableAggFunction

SqlSplittableAggFunction.AbstractSumSplitter, SqlSplittableAggFunction.CountSplitter, SqlSplittableAggFunction.Registry<E>, SqlSplittableAggFunction.SelfSplitter, SqlSplittableAggFunction.Sum0Splitter, SqlSplittableAggFunction.SumSplitter

Field Summary

Fields

Modifier and Type	Field	Description
static SqlSplittableAggFunction.SelfSplitter	INSTANCE

Constructor Summary

Constructors

Constructor	Description
SelfSplitter()

Method Summary

Modifier and Type	Method	Description
AggregateCall	other(RelDataTypeFactory typeFactory, AggregateCall e)	Called to generate an aggregate for the other side of the join than the side aggregate call's arguments come from.
RexNode	singleton(RexBuilder rexBuilder, RelDataType inputRowType, AggregateCall aggregateCall)	Generates an expression for the value of the aggregate function when applied to a single row.
AggregateCall	split(AggregateCall aggregateCall, Mappings.TargetMapping mapping)
AggregateCall	topSplit(RexBuilder rexBuilder, SqlSplittableAggFunction.Registry<RexNode> extra, int offset, RelDataType inputRowType, AggregateCall aggregateCall, int leftSubTotal, int rightSubTotal)	Generates an aggregate call to merge sub-totals.

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final SqlSplittableAggFunction.SelfSplitter INSTANCE

Constructor Detail

SelfSplitter

public SelfSplitter()

Method Detail

singleton

public RexNode singleton(RexBuilder rexBuilder,
                         RelDataType inputRowType,
                         AggregateCall aggregateCall)

Description copied from interface: SqlSplittableAggFunction

Generates an expression for the value of the aggregate function when applied to a single row.

For example, if there is one row:

• SUM(x) is x
• MIN(x) is x
• MAX(x) is x
• COUNT(x) is CASE WHEN x IS NOT NULL THEN 1 ELSE 0 END 1 which can be simplified to 1 if x is never null
• COUNT(*) is 1

Specified by:

singleton in interface SqlSplittableAggFunction

Parameters:

rexBuilder - Rex builder

inputRowType - Input row type

aggregateCall - Aggregate call

Returns:

Expression for single row

split

public AggregateCall split(AggregateCall aggregateCall,
                           Mappings.TargetMapping mapping)

Specified by:

split in interface SqlSplittableAggFunction

other

public AggregateCall other(RelDataTypeFactory typeFactory,
                           AggregateCall e)

Description copied from interface: SqlSplittableAggFunction

Called to generate an aggregate for the other side of the join than the side aggregate call's arguments come from. Returns null if no aggregate is required.

Specified by:

other in interface SqlSplittableAggFunction

topSplit

public AggregateCall topSplit(RexBuilder rexBuilder,
                              SqlSplittableAggFunction.Registry<RexNode> extra,
                              int offset,
                              RelDataType inputRowType,
                              AggregateCall aggregateCall,
                              int leftSubTotal,
                              int rightSubTotal)

Description copied from interface: SqlSplittableAggFunction

Generates an aggregate call to merge sub-totals.

Most implementations will add a single aggregate call to aggCalls, and return a RexInputRef that points to it.

Specified by:

topSplit in interface SqlSplittableAggFunction

Parameters:

rexBuilder - Rex builder

extra - Place to define extra input expressions

offset - Offset due to grouping columns (and indicator columns if applicable)

inputRowType - Input row type

aggregateCall - Source aggregate call

leftSubTotal - Ordinal of the sub-total coming from the left side of the join, or -1 if there is no such sub-total

rightSubTotal - Ordinal of the sub-total coming from the right side of the join, or -1 if there is no such sub-total

Returns:

Aggregate call