org.h2.expression.aggregate

Class Aggregate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.analysis.DataAnalysisOperation

org.h2.expression.aggregate.AbstractAggregate

org.h2.expression.aggregate.Aggregate

All Implemented Interfaces:

ExpressionWithFlags, HasSQL, Typed

public class Aggregate
extends AbstractAggregate
implements ExpressionWithFlags

Implements the integrated aggregate functions, such as COUNT, MAX, SUM.

Field Summary

Fields inherited from class org.h2.expression.aggregate.AbstractAggregate

args, distinct, filterCondition, type

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

Constructor Summary

Constructors

Constructor and Description
Aggregate(AggregateType aggregateType, Expression[] args, Select select, boolean distinct) Create a new aggregate object.

Method Summary

Modifier and Type	Method and Description
protected java.lang.Object	createAggregateData() Create aggregate data object specific to the subclass.
Value	getAggregatedValue(SessionLocal session, java.lang.Object aggregateData) Returns aggregated value.
AggregateType	getAggregateType() Returns the type of this aggregate.
static AggregateType	getAggregateType(java.lang.String name) Get the aggregate type for this name, or -1 if no aggregate has been found.
int	getCost() Estimate the cost to process the expression.
java.lang.Object	getExtraArguments() Returns the additional arguments.
int	getFlags() Returns the flags.
protected int	getNumExpressions() Returns the number of expressions, excluding OVER clause.
Select	getSelect() Returns the select statement.
java.lang.StringBuilder	getUnenclosedSQL(java.lang.StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.
Value	getValue(SessionLocal session) Return the resulting value for the current row.
boolean	isDistinct() Returns if distinct is used.
boolean	isEverything(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.
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.
protected void	rememberExpressions(SessionLocal session, Value[] array) Stores current values of expressions into the specified array.
void	setEvaluatable(TableFilter tableFilter, boolean b) Tell the expression columns whether the table filter can return values now.
void	setExtraArguments(java.lang.Object extraArguments) Sets the additional arguments.
void	setFlags(int flags) Set the flags for this expression.
void	setOrderByList(java.util.ArrayList<QueryOrderBy> orderByList) Set the order for ARRAY_AGG() or GROUP_CONCAT() aggregate.
protected void	updateAggregate(SessionLocal session, java.lang.Object aggregateData) Updates an aggregate value.
protected 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.aggregate.AbstractAggregate

appendTailConditions, getOrderedResultLoop, getSubexpression, getSubexpressionCount, getType, isAggregate, setFilterCondition, updateAggregate

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

createOrder, getGroupData, getOverOrderBySort, getWindowData, mapColumns, setOverCondition, updateAggregate, updateOrderedAggregate

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, 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

Constructor Detail

Aggregate

public Aggregate(AggregateType aggregateType,
                 Expression[] args,
                 Select select,
                 boolean distinct)

Create a new aggregate object.

Parameters:

aggregateType - the aggregate type

args - the aggregated expressions

select - the select statement

distinct - if distinct is used

Method Detail

getAggregateType

public static AggregateType getAggregateType(java.lang.String name)

Get the aggregate type for this name, or -1 if no aggregate has been found.

Parameters:

name - the aggregate function name

Returns:

null if no aggregate function has been found, or the aggregate type

setOrderByList

public void setOrderByList(java.util.ArrayList<QueryOrderBy> orderByList)

Set the order for ARRAY_AGG() or GROUP_CONCAT() aggregate.

Parameters:

orderByList - the order by list

getAggregateType

public AggregateType getAggregateType()

Returns the type of this aggregate.

Returns:

the type of this aggregate

setExtraArguments

public void setExtraArguments(java.lang.Object extraArguments)

Sets the additional arguments.

Parameters:

extraArguments - the additional arguments

getExtraArguments

public java.lang.Object getExtraArguments()

Returns the additional arguments.

Returns:

the additional arguments

setFlags

public void setFlags(int flags)

Description copied from interface: ExpressionWithFlags

Set the flags for this expression.

Specified by:

setFlags in interface ExpressionWithFlags

Parameters:

flags - the flags to set

getFlags

public int getFlags()

Description copied from interface: ExpressionWithFlags

Returns the flags.

Specified by:

getFlags in interface ExpressionWithFlags

Returns:

the flags

updateAggregate

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

Description copied from class: AbstractAggregate

Updates an aggregate value.

Specified by:

updateAggregate in class AbstractAggregate

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 AbstractAggregate

Parameters:

session - the session

stage - select stage

getNumExpressions

protected int getNumExpressions()

Description copied from class: DataAnalysisOperation

Returns the number of expressions, excluding OVER clause.

Specified by:

getNumExpressions in class DataAnalysisOperation

Returns:

the number of expressions

rememberExpressions

protected void rememberExpressions(SessionLocal session,
                                   Value[] array)

Description copied from class: DataAnalysisOperation

Stores current values of expressions into the specified array.

Specified by:

rememberExpressions in class DataAnalysisOperation

Parameters:

session - the session

array - array to store values of expressions

updateFromExpressions

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

Description copied from class: AbstractAggregate

Updates the provided aggregate data from the remembered expressions.

Specified by:

updateFromExpressions in class AbstractAggregate

Parameters:

session - the session

aggregateData - aggregate data

array - values of expressions

createAggregateData

protected java.lang.Object createAggregateData()

Description copied from class: DataAnalysisOperation

Create aggregate data object specific to the subclass.

Specified by:

createAggregateData in class DataAnalysisOperation

Returns:

aggregate-specific data object.

getValue

public Value getValue(SessionLocal session)

Description copied from class: Expression

Return the resulting value for the current row.

Overrides:

getValue in class DataAnalysisOperation

Parameters:

session - the session

Returns:

the result

getAggregatedValue

public Value getAggregatedValue(SessionLocal session,
                                java.lang.Object aggregateData)

Description copied from class: DataAnalysisOperation

Returns aggregated value.

Specified by:

getAggregatedValue in class DataAnalysisOperation

Parameters:

session - the session

aggregateData - the aggregate data

Returns:

aggregated value.

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 AbstractAggregate

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 AbstractAggregate

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 AbstractAggregate

Parameters:

tableFilter - the table filter

b - true if the table filter can return value

getUnenclosedSQL

public java.lang.StringBuilder getUnenclosedSQL(java.lang.StringBuilder builder,
                                                int sqlFlags)

Description copied from class: Expression

Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.

Specified by:

getUnenclosedSQL in class Expression

Parameters:

builder - string builder

sqlFlags - formatting flags

Returns:

the specified string builder

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Expression

Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.

Overrides:

isEverything in class DataAnalysisOperation

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled

getCost

public int getCost()

Description copied from class: Expression

Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.

Specified by:

getCost in class Expression

Returns:

the estimated cost

getSelect

public Select getSelect()

Returns the select statement.

Returns:

the select statement

isDistinct

public boolean isDistinct()

Returns if distinct is used.

Returns:

if distinct is used