com.hazelcast.org.apache.calcite.rel.core.Union 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 com.hazelcast.com.liance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.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.rel.core;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.RelInput;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMdUtil;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import java.util.List;
/**
* Relational expression that returns the union of the rows of its inputs,
* optionally eliminating duplicates.
*
* Corresponds to SQL {@code UNION} and {@code UNION ALL}.
*/
public abstract class Union extends SetOp {
//~ Constructors -----------------------------------------------------------
protected Union(
RelOptCluster cluster,
RelTraitSet traits,
List inputs,
boolean all) {
super(cluster, traits, inputs, SqlKind.UNION, all);
}
/**
* Creates a Union by parsing serialized output.
*/
protected Union(RelInput input) {
super(input);
}
//~ Methods ----------------------------------------------------------------
@Override public double estimateRowCount(RelMetadataQuery mq) {
double dRows = RelMdUtil.getUnionAllRowCount(mq, this);
if (!all) {
dRows *= 0.5;
}
return dRows;
}
@Deprecated // to be removed before 2.0
public static double estimateRowCount(RelNode rel) {
final RelMetadataQuery mq = rel.getCluster().getMetadataQuery();
return RelMdUtil.getUnionAllRowCount(mq, (Union) rel);
}
}