org.h2.expression.aggregate

Class AbstractAggregate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.analysis.DataAnalysisOperation

org.h2.expression.aggregate.AbstractAggregate

All Implemented Interfaces:

HasSQL, Typed

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

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

Fields inherited from interface org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

Method Summary

Modifier and Type	Method and Description
protected java.lang.StringBuilder	appendTailConditions(java.lang.StringBuilder builder, int sqlFlags, boolean forceOrderBy) Used to create SQL for the OVER and FILTER clauses.
Expression	getFilterCondition() Returns the FILTER condition.
protected void	getOrderedResultLoop(SessionLocal 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.
Expression	getSubexpression(int index) Returns subexpression with specified index.
int	getSubexpressionCount() Returns count of subexpressions.
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(SessionLocal 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(SessionLocal session, java.lang.Object aggregateData) Updates an aggregate value.
protected void	updateAggregate(SessionLocal session, SelectGroups groupData, int groupRowId) Update a row of an aggregate.
protected abstract void	updateFromExpressions(SessionLocal session, java.lang.Object aggregateData, Value[] array) Updates the provided aggregate data from the remembered expressions.
protected void	updateGroupAggregates(SessionLocal 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, getOverCondition, getOverOrderBySort, getValue, getWindowData, isEverything, mapColumns, rememberExpressions, setOverCondition, updateAggregate, updateOrderedAggregate

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getCost, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getUnenclosedSQL, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimizeCondition, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.util.HasSQL

getTraceSQL

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

getFilterCondition

public Expression getFilterCondition()

Returns the FILTER condition.

Returns:

the FILTER Condition

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 be unknown before the optimization phase.

Specified by:

getType in interface Typed

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(SessionLocal 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(SessionLocal 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(SessionLocal 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(SessionLocal 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(SessionLocal session,
                                        java.lang.Object aggregateData)

Updates an aggregate value.

Parameters:

session - the session

aggregateData - aggregate data

updateGroupAggregates

protected void updateGroupAggregates(SessionLocal 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,
                                                       int sqlFlags,
                                                       boolean forceOrderBy)

Description copied from class: DataAnalysisOperation

Used to create SQL for the OVER and FILTER clauses.

Overrides:

appendTailConditions in class DataAnalysisOperation

Parameters:

builder - string builder

sqlFlags - formatting flags

forceOrderBy - whether synthetic ORDER BY clause should be generated when it is missing

Returns:

the builder object

getSubexpressionCount

public int getSubexpressionCount()

Description copied from class: Expression

Returns count of subexpressions.

Overrides:

getSubexpressionCount in class Expression

Returns:

count of subexpressions

getSubexpression

public Expression getSubexpression(int index)

Description copied from class: Expression

Returns subexpression with specified index.

Overrides:

getSubexpression in class Expression

Parameters:

index - 0-based index

Returns:

subexpression with specified index, may be null