/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.expression;
import org.h2.engine.SessionLocal;
import org.h2.table.ColumnResolver;
import org.h2.table.TableFilter;
import org.h2.util.ParserUtil;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
/**
* A column alias as in SELECT 'Hello' AS NAME ...
*/
public final class Alias extends Expression {
private final String alias;
private Expression expr;
private final boolean aliasColumnName;
public Alias(Expression expression, String alias, boolean aliasColumnName) {
this.expr = expression;
this.alias = alias;
this.aliasColumnName = aliasColumnName;
}
@Override
public Expression getNonAliasExpression() {
return expr;
}
@Override
public Value getValue(SessionLocal session) {
return expr.getValue(session);
}
@Override
public TypeInfo getType() {
return expr.getType();
}
@Override
public void mapColumns(ColumnResolver resolver, int level, int state) {
expr.mapColumns(resolver, level, state);
}
@Override
public Expression optimize(SessionLocal session) {
expr = expr.optimize(session);
return this;
}
@Override
public void setEvaluatable(TableFilter tableFilter, boolean b) {
expr.setEvaluatable(tableFilter, b);
}
@Override
public boolean isIdentity() {
return expr.isIdentity();
}
@Override
public StringBuilder getUnenclosedSQL(StringBuilder builder, int sqlFlags) {
expr.getUnenclosedSQL(builder, sqlFlags).append(" AS ");
return ParserUtil.quoteIdentifier(builder, alias, sqlFlags);
}
@Override
public void updateAggregate(SessionLocal session, int stage) {
expr.updateAggregate(session, stage);
}
@Override
public String getAlias(SessionLocal session, int columnIndex) {
return alias;
}
@Override
public String getColumnNameForView(SessionLocal session, int columnIndex) {
return alias;
}
@Override
public int getNullable() {
return expr.getNullable();
}
@Override
public boolean isEverything(ExpressionVisitor visitor) {
return expr.isEverything(visitor);
}
@Override
public int getCost() {
return expr.getCost();
}
@Override
public String getSchemaName() {
if (aliasColumnName) {
return null;
}
return expr.getSchemaName();
}
@Override
public String getTableName() {
if (aliasColumnName) {
return null;
}
return expr.getTableName();
}
@Override
public String getColumnName(SessionLocal session, int columnIndex) {
if (!(expr instanceof ExpressionColumn) || aliasColumnName) {
return alias;
}
return expr.getColumnName(session, columnIndex);
}
}