org.h2.expression.aggregate

Class AbstractAggregate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.analysis.DataAnalysisOperation

org.h2.expression.aggregate.AbstractAggregate

Direct Known Subclasses:

Aggregate, JavaAggregate

public abstract class AbstractAggregate
extends DataAnalysisOperation

A base class for aggregate functions.

Field Summary

Fields

Modifier and Type	Field and Description
protected Expression[]	args The arguments.
protected boolean	distinct is this a DISTINCT aggregate
protected Expression	filterCondition FILTER condition for aggregate
protected TypeInfo	type The type of the result.

Fields inherited from class org.h2.expression.analysis.DataAnalysisOperation

over, overOrderBySort, select, STAGE_GROUP, STAGE_RESET, STAGE_WINDOW

Fields inherited from class org.h2.expression.Expression

MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL

Method Summary

Methods

Modifier and Type	Method and Description
protected java.lang.StringBuilder	appendTailConditions(java.lang.StringBuilder builder, boolean alwaysQuote) Used to create SQL for the OVER and FILTER clauses.
protected void	getOrderedResultLoop(Session session, java.util.HashMap<java.lang.Integer,Value> result, java.util.ArrayList<Value[]> ordered, int rowIdColumn) Returns result of this window function or window aggregate.
TypeInfo	getType() Returns the data type.
boolean	isAggregate() Checks whether this expression is an aggregate function.
void	mapColumnsAnalysis(ColumnResolver resolver, int level, int innerState) Map the columns of the resolver to expression columns.
Expression	optimize(Session session) Try to optimize the expression.
void	setEvaluatable(TableFilter tableFilter, boolean b) Tell the expression columns whether the table filter can return values now.
void	setFilterCondition(Expression filterCondition) Sets the FILTER condition.
protected abstract void	updateAggregate(Session session, java.lang.Object aggregateData) Updates an aggregate value.
protected void	updateAggregate(Session session, SelectGroups groupData, int groupRowId) Update a row of an aggregate.
protected abstract void	updateFromExpressions(Session session, java.lang.Object aggregateData, Value[] array) Updates the provided aggregate data from the remembered expressions.
protected void	updateGroupAggregates(Session session, int stage) Invoked when processing group stage of grouped window queries to update arguments of this aggregate.

Methods inherited from class org.h2.expression.analysis.DataAnalysisOperation

createAggregateData, createOrder, getAggregatedValue, getGroupData, getNumExpressions, getOverOrderBySort, getValue, getWindowData, isEverything, mapColumns, rememberExpressions, setOverCondition, updateAggregate, updateOrderedAggregate

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getCost, getExpressionColumns, getExpressionColumns, getExpressionColumns, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSubexpression, getSubexpressionCount, getTableAlias, getTableName, getUnenclosedSQL, isAutoIncrement, isConstant, isGeneratedKey, isValueSet, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Field Detail

distinct

protected final boolean distinct

is this a DISTINCT aggregate

args

protected final Expression[] args

The arguments.

filterCondition

protected Expression filterCondition

FILTER condition for aggregate

type

protected TypeInfo type

The type of the result.

Method Detail

isAggregate

public final boolean isAggregate()

Description copied from class: DataAnalysisOperation

Checks whether this expression is an aggregate function.

Specified by:

isAggregate in class DataAnalysisOperation

Returns:

true if this is an aggregate function (including aggregates with OVER clause), false if this is a window function

setFilterCondition

public void setFilterCondition(Expression filterCondition)

Sets the FILTER condition.

Parameters:

filterCondition - FILTER condition

getType

public TypeInfo getType()

Description copied from class: Expression

Returns the data type. The data type may not be known before the optimization phase.

Specified by:

getType in class Expression

Returns:

the data type

mapColumnsAnalysis

public void mapColumnsAnalysis(ColumnResolver resolver,
                      int level,
                      int innerState)

Description copied from class: DataAnalysisOperation

Map the columns of the resolver to expression columns.

Overrides:

mapColumnsAnalysis in class DataAnalysisOperation

Parameters:

resolver - the column resolver

level - the subquery nesting level

innerState - one of the Expression MAP_IN_* values

optimize

public Expression optimize(Session session)

Description copied from class: Expression

Try to optimize the expression.

Overrides:

optimize in class DataAnalysisOperation

Parameters:

session - the session

Returns:

the optimized expression

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                  boolean b)

Description copied from class: Expression

Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.

Overrides:

setEvaluatable in class DataAnalysisOperation

Parameters:

tableFilter - the table filter

b - true if the table filter can return value

getOrderedResultLoop

protected void getOrderedResultLoop(Session session,
                        java.util.HashMap<java.lang.Integer,Value> result,
                        java.util.ArrayList<Value[]> ordered,
                        int rowIdColumn)

Description copied from class: DataAnalysisOperation

Returns result of this window function or window aggregate. This method may not be called on window aggregate without window order clause.

Specified by:

getOrderedResultLoop in class DataAnalysisOperation

Parameters:

session - the session

result - the map to append result to

ordered - ordered data

rowIdColumn - the index of row id value

updateFromExpressions

protected abstract void updateFromExpressions(Session session,
                         java.lang.Object aggregateData,
                         Value[] array)

Updates the provided aggregate data from the remembered expressions.

Parameters:

session - the session

aggregateData - aggregate data

array - values of expressions

updateAggregate

protected void updateAggregate(Session session,
                   SelectGroups groupData,
                   int groupRowId)

Description copied from class: DataAnalysisOperation

Update a row of an aggregate.

Specified by:

updateAggregate in class DataAnalysisOperation

Parameters:

session - the database session

groupData - data for the aggregate group

groupRowId - row id of group

updateAggregate

protected abstract void updateAggregate(Session session,
                   java.lang.Object aggregateData)

Updates an aggregate value.

Parameters:

session - the session

aggregateData - aggregate data

updateGroupAggregates

protected void updateGroupAggregates(Session session,
                         int stage)

Description copied from class: DataAnalysisOperation

Invoked when processing group stage of grouped window queries to update arguments of this aggregate.

Overrides:

updateGroupAggregates in class DataAnalysisOperation

Parameters:

session - the session

stage - select stage

appendTailConditions

protected java.lang.StringBuilder appendTailConditions(java.lang.StringBuilder builder,
                                           boolean alwaysQuote)

Description copied from class: DataAnalysisOperation

Used to create SQL for the OVER and FILTER clauses.

Overrides:

appendTailConditions in class DataAnalysisOperation

Parameters:

builder - string builder

alwaysQuote - quote all identifiers

Returns:

the builder object