Package org.h2.command.query

Class SelectListColumnResolver

java.lang.Object

org.h2.command.query.SelectListColumnResolver

All Implemented Interfaces:

ColumnResolver

public class SelectListColumnResolver
extends java.lang.Object
implements ColumnResolver

This class represents a column resolver for the column list of a SELECT statement. It is used to resolve select column aliases in the HAVING clause. Example:

SELECT X/3 AS A, COUNT(*) FROM SYSTEM_RANGE(1, 10) GROUP BY A HAVING A > 2;

Field Summary

Fields

Modifier and Type	Field	Description
private Column[]	columns
private Expression[]	expressions
private Select	select

Constructor Summary

Constructors

Constructor	Description
SelectListColumnResolver(Select select)

Method Summary

Modifier and Type	Method	Description
Column	findColumn(java.lang.String name)	Get the column with the specified name.
Column[]	getColumns()	Get the column list.
Select	getSelect()	Get the select statement.
Value	getValue(Column column)	Get the value for the given column.
Expression	optimize(ExpressionColumn expressionColumn, Column column)	Get the expression that represents this column.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.table.ColumnResolver

getColumnName, getRowIdColumn, getSchemaName, getSystemColumns, getTableAlias, getTableFilter, hasDerivedColumnList

Field Detail

select

private final Select select

expressions

private final Expression[] expressions

columns

private final Column[] columns

Constructor Detail

SelectListColumnResolver

SelectListColumnResolver(Select select)

Method Detail

getColumns

public Column[] getColumns()

Description copied from interface: ColumnResolver

Get the column list.

Specified by:

getColumns in interface ColumnResolver

Returns:

the column list

findColumn

public Column findColumn(java.lang.String name)

Description copied from interface: ColumnResolver

Get the column with the specified name.

Specified by:

findColumn in interface ColumnResolver

Parameters:

name - the column name, must be a derived name if this column resolver has a derived column list

Returns:

the column with the specified name, or null

getSelect

public Select getSelect()

Description copied from interface: ColumnResolver

Get the select statement.

Specified by:

getSelect in interface ColumnResolver

Returns:

the select statement

getValue

public Value getValue(Column column)

Description copied from interface: ColumnResolver

Get the value for the given column.

Specified by:

getValue in interface ColumnResolver

Parameters:

column - the column

Returns:

the value

optimize

public Expression optimize(ExpressionColumn expressionColumn,
                           Column column)

Description copied from interface: ColumnResolver

Get the expression that represents this column.

Specified by:

optimize in interface ColumnResolver

Parameters:

expressionColumn - the expression column

column - the column

Returns:

the optimized expression