org.h2.command.query

类 SelectListColumnResolver

java.lang.Object

org.h2.command.query.SelectListColumnResolver

所有已实现的接口:

ColumnResolver

public class SelectListColumnResolver
extends 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;

作者:

Thomas Mueller

方法概要

限定符和类型	方法和说明
Column	findColumn(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.

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.h2.table.ColumnResolver

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

方法详细资料

getColumns

public Column[] getColumns()

从接口复制的说明: ColumnResolver

Get the column list.

指定者:

getColumns 在接口中 ColumnResolver

返回:

the column list

findColumn

public Column findColumn(String name)

从接口复制的说明: ColumnResolver

Get the column with the specified name.

指定者:

findColumn 在接口中 ColumnResolver

参数:

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

返回:

the column with the specified name, or null

getSelect

public Select getSelect()

从接口复制的说明: ColumnResolver

Get the select statement.

指定者:

getSelect 在接口中 ColumnResolver

返回:

the select statement

getValue

public Value getValue(Column column)

从接口复制的说明: ColumnResolver

Get the value for the given column.

指定者:

getValue 在接口中 ColumnResolver

参数:

column - the column

返回:

the value

optimize

public Expression optimize(ExpressionColumn expressionColumn,
                           Column column)

从接口复制的说明: ColumnResolver

Get the expression that represents this column.

指定者:

optimize 在接口中 ColumnResolver

参数:

expressionColumn - the expression column

column - the column

返回:

the optimized expression