org.h2.expression.analysis

类 WindowFunction

java.lang.Object

org.h2.expression.Expression

org.h2.expression.analysis.DataAnalysisOperation

org.h2.expression.analysis.WindowFunction

所有已实现的接口:

HasSQL, Typed

public class WindowFunction
extends DataAnalysisOperation

A window function.

字段概要

从类继承的字段 org.h2.expression.analysis.DataAnalysisOperation

over, overOrderBySort, select, STAGE_GROUP, STAGE_RESET, STAGE_WINDOW

从类继承的字段 org.h2.expression.Expression

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

从接口继承的字段 org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

构造器概要

构造器

构造器和说明
WindowFunction(WindowFunctionType type, Select select, Expression[] args) Creates new instance of a window function.

方法概要

限定符和类型	方法和说明
protected Object	createAggregateData() Create aggregate data object specific to the subclass.
protected Value	getAggregatedValue(SessionLocal session, Object aggregateData) Returns aggregated value.
int	getCost() Estimate the cost to process the expression.
WindowFunctionType	getFunctionType() Returns the type of this function.
static int	getMaxArgumentCount(WindowFunctionType type) Returns maximal number of arguments for the specified type.
static int	getMinArgumentCount(WindowFunctionType type) Returns minimal number of arguments for the specified type.
protected int	getNumExpressions() Returns the number of expressions, excluding OVER clause.
protected void	getOrderedResultLoop(SessionLocal session, HashMap<Integer,Value> result, ArrayList<Value[]> ordered, int rowIdColumn) Returns result of this window function or window aggregate.
TypeInfo	getType() Returns the data type.
StringBuilder	getUnenclosedSQL(StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.
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.
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	setFromLast(boolean fromLast) Sets FROM FIRST or FROM LAST clause value.
void	setIgnoreNulls(boolean ignoreNulls) Sets RESPECT NULLS or IGNORE NULLS clause value.
protected void	updateAggregate(SessionLocal session, SelectGroups groupData, int groupRowId) Update a row of an aggregate.
protected void	updateGroupAggregates(SessionLocal session, int stage) Invoked when processing group stage of grouped window queries to update arguments of this aggregate.

从类继承的方法 org.h2.expression.analysis.DataAnalysisOperation

appendTailConditions, createOrder, getGroupData, getOverCondition, getOverOrderBySort, getValue, getWindowData, isEverything, mapColumns, setOverCondition, updateAggregate, updateOrderedAggregate

从类继承的方法 org.h2.expression.Expression

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

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.h2.util.HasSQL

getTraceSQL

构造器详细资料

WindowFunction

public WindowFunction(WindowFunctionType type,
                      Select select,
                      Expression[] args)

Creates new instance of a window function.

参数:

type - the type

select - the select statement

args - arguments, or null

方法详细资料

getMinArgumentCount

public static int getMinArgumentCount(WindowFunctionType type)

Returns minimal number of arguments for the specified type.

参数:

type - the type of a window function

返回:

minimal number of arguments

getMaxArgumentCount

public static int getMaxArgumentCount(WindowFunctionType type)

Returns maximal number of arguments for the specified type.

参数:

type - the type of a window function

返回:

maximal number of arguments

getFunctionType

public WindowFunctionType getFunctionType()

Returns the type of this function.

返回:

the type of this function

setFromLast

public void setFromLast(boolean fromLast)

Sets FROM FIRST or FROM LAST clause value.

参数:

fromLast - whether FROM LAST clause was specified.

setIgnoreNulls

public void setIgnoreNulls(boolean ignoreNulls)

Sets RESPECT NULLS or IGNORE NULLS clause value.

参数:

ignoreNulls - whether IGNORE NULLS clause was specified

isAggregate

public boolean isAggregate()

从类复制的说明: DataAnalysisOperation

Checks whether this expression is an aggregate function.

指定者:

isAggregate 在类中 DataAnalysisOperation

返回:

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

updateAggregate

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

从类复制的说明: DataAnalysisOperation

Update a row of an aggregate.

指定者:

updateAggregate 在类中 DataAnalysisOperation

参数:

session - the database session

groupData - data for the aggregate group

groupRowId - row id of group

updateGroupAggregates

protected void updateGroupAggregates(SessionLocal session,
                                     int stage)

从类复制的说明: DataAnalysisOperation

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

覆盖:

updateGroupAggregates 在类中 DataAnalysisOperation

参数:

session - the session

stage - select stage

getNumExpressions

protected int getNumExpressions()

从类复制的说明: DataAnalysisOperation

Returns the number of expressions, excluding OVER clause.

指定者:

getNumExpressions 在类中 DataAnalysisOperation

返回:

the number of expressions

rememberExpressions

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

从类复制的说明: DataAnalysisOperation

Stores current values of expressions into the specified array.

指定者:

rememberExpressions 在类中 DataAnalysisOperation

参数:

session - the session

array - array to store values of expressions

createAggregateData

protected Object createAggregateData()

从类复制的说明: DataAnalysisOperation

Create aggregate data object specific to the subclass.

指定者:

createAggregateData 在类中 DataAnalysisOperation

返回:

aggregate-specific data object.

getOrderedResultLoop

protected void getOrderedResultLoop(SessionLocal session,
                                    HashMap<Integer,Value> result,
                                    ArrayList<Value[]> ordered,
                                    int rowIdColumn)

从类复制的说明: DataAnalysisOperation

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

指定者:

getOrderedResultLoop 在类中 DataAnalysisOperation

参数:

session - the session

result - the map to append result to

ordered - ordered data

rowIdColumn - the index of row id value

getAggregatedValue

protected Value getAggregatedValue(SessionLocal session,
                                   Object aggregateData)

从类复制的说明: DataAnalysisOperation

Returns aggregated value.

指定者:

getAggregatedValue 在类中 DataAnalysisOperation

参数:

session - the session

aggregateData - the aggregate data

返回:

aggregated value.

mapColumnsAnalysis

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

从类复制的说明: DataAnalysisOperation

Map the columns of the resolver to expression columns.

覆盖:

mapColumnsAnalysis 在类中 DataAnalysisOperation

参数:

resolver - the column resolver

level - the subquery nesting level

innerState - one of the Expression MAP_IN_* values

optimize

public Expression optimize(SessionLocal session)

从类复制的说明: Expression

Try to optimize the expression.

覆盖:

optimize 在类中 DataAnalysisOperation

参数:

session - the session

返回:

the optimized expression

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean b)

从类复制的说明: Expression

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

覆盖:

setEvaluatable 在类中 DataAnalysisOperation

参数:

tableFilter - the table filter

b - true if the table filter can return value

getType

public TypeInfo getType()

从类复制的说明: Expression

Returns the data type. The data type may be unknown before the optimization phase.

指定者:

getType 在接口中 Typed

指定者:

getType 在类中 Expression

返回:

the data type

getUnenclosedSQL

public StringBuilder getUnenclosedSQL(StringBuilder builder,
                                      int sqlFlags)

从类复制的说明: 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.

指定者:

getUnenclosedSQL 在类中 Expression

参数:

builder - string builder

sqlFlags - formatting flags

返回:

the specified string builder

getCost

public int getCost()

从类复制的说明: Expression

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

指定者:

getCost 在类中 Expression

返回:

the estimated cost