com.hazelcast.org.apache.calcite.sql.validate.AggregatingScope Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.org.apache.calcite.sql.validate;
import com.hazelcast.org.apache.calcite.sql.SqlNode;
/**
* An extension to the {@link SqlValidatorScope} interface which indicates that
* the scope is aggregating.
*
* A scope which is aggregating must implement this interface. Such a scope
* will return the same set of identifiers as its parent scope, but some of
* those identifiers may not be accessible because they are not in the GROUP BY
* clause.
*/
public interface AggregatingScope extends SqlValidatorScope {
//~ Methods ----------------------------------------------------------------
/**
* Checks whether an expression is constant within the GROUP BY clause. If
* the expression completely matches an expression in the GROUP BY clause,
* returns true. If the expression is constant within the group, but does
* not exactly match, returns false. If the expression is not constant,
* throws an exception. Examples:
*
*
* - If we are 'f(b, c)' in 'SELECT a + f(b, c) FROM t GROUP BY a', then
* the whole expression matches a group column. Return true.
*
- Just an ordinary expression in a GROUP BY query, such as 'f(SUM(a),
* 1, b)' in 'SELECT f(SUM(a), 1, b) FROM t GROUP BY b'. Returns false.
*
- Illegal expression, such as 'f(5, a, b)' in 'SELECT f(a, b) FROM t
* GROUP BY a'. Throws when it enounters the 'b' operand, because it is not
* in the group clause.
*
*/
boolean checkAggregateExpr(SqlNode expr, boolean deep);
}