org.h2.expression.analysis

Class Window

java.lang.Object

org.h2.expression.analysis.Window

public final class Window
extends java.lang.Object

Window clause.

Constructor Summary

Constructors

Constructor and Description
Window(java.lang.String parent, java.util.ArrayList<Expression> partitionBy, java.util.ArrayList<QueryOrderBy> orderBy, WindowFrame frame) Creates a new instance of window clause.

Method Summary

Modifier and Type	Method and Description
static void	appendOrderBy(java.lang.StringBuilder builder, java.util.ArrayList<QueryOrderBy> orderBy, int sqlFlags, boolean forceOrderBy) Appends ORDER BY clause to the specified builder.
Value	getCurrentKey(SessionLocal session) Returns the key for the current group.
java.util.ArrayList<QueryOrderBy>	getOrderBy() Returns ORDER BY clause.
java.lang.StringBuilder	getSQL(java.lang.StringBuilder builder, int sqlFlags, boolean forceOrderBy) Appends SQL representation to the specified builder.
WindowFrame	getWindowFrame() Returns window frame, or null.
boolean	isOrdered() Returns true if window ordering clause is specified or ROWS unit is used.
void	mapColumns(ColumnResolver resolver, int level) Map the columns of the resolver to expression columns.
void	optimize(SessionLocal session) Try to optimize the window conditions.
void	setEvaluatable(TableFilter tableFilter, boolean value) Tell the expression columns whether the table filter can return values now.
java.lang.String	toString()
void	updateAggregate(SessionLocal session, int stage) Update an aggregate value.

Methods inherited from class java.lang.Object

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

Constructor Detail

Window

public Window(java.lang.String parent,
              java.util.ArrayList<Expression> partitionBy,
              java.util.ArrayList<QueryOrderBy> orderBy,
              WindowFrame frame)

Creates a new instance of window clause.

Parameters:

parent - name of the parent window

partitionBy - PARTITION BY clause, or null

orderBy - ORDER BY clause, or null

frame - window frame clause, or null

Method Detail

appendOrderBy

public static void appendOrderBy(java.lang.StringBuilder builder,
                                 java.util.ArrayList<QueryOrderBy> orderBy,
                                 int sqlFlags,
                                 boolean forceOrderBy)

Appends ORDER BY clause to the specified builder.

Parameters:

builder - string builder

orderBy - ORDER BY clause, or null

sqlFlags - formatting flags

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

mapColumns

public void mapColumns(ColumnResolver resolver,
                       int level)

Map the columns of the resolver to expression columns.

Parameters:

resolver - the column resolver

level - the subquery nesting level

See Also:

Expression.mapColumns(ColumnResolver, int, int)

optimize

public void optimize(SessionLocal session)

Try to optimize the window conditions.

Parameters:

session - the session

setEvaluatable

public void setEvaluatable(TableFilter tableFilter,
                           boolean value)

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

Parameters:

tableFilter - the table filter

value - true if the table filter can return value

See Also:

Expression.setEvaluatable(TableFilter, boolean)

getOrderBy

public java.util.ArrayList<QueryOrderBy> getOrderBy()

Returns ORDER BY clause.

Returns:

ORDER BY clause, or null

getWindowFrame

public WindowFrame getWindowFrame()

Returns window frame, or null.

Returns:

window frame, or null

isOrdered

public boolean isOrdered()

Returns true if window ordering clause is specified or ROWS unit is used.

Returns:

true if window ordering clause is specified or ROWS unit is used

getCurrentKey

public Value getCurrentKey(SessionLocal session)

Returns the key for the current group.

Parameters:

session - session

Returns:

key for the current group, or null

getSQL

public java.lang.StringBuilder getSQL(java.lang.StringBuilder builder,
                                      int sqlFlags,
                                      boolean forceOrderBy)

Appends SQL representation to the specified builder.

Parameters:

builder - string builder

sqlFlags - formatting flags

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

Returns:

the specified string builder

See Also:

Expression.getSQL(StringBuilder, int, int)

updateAggregate

public void updateAggregate(SessionLocal session,
                            int stage)

Update an aggregate value.

Parameters:

session - the session

stage - select stage

See Also:

Expression.updateAggregate(SessionLocal, int)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object