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[CALCITE-7362] Add rule to transform WHERE clauses into filtered aggregates
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‎core/src/main/java/org/apache/calcite/rel/rules/AggregateFilterToFilteredAggregateRule.java‎

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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to you under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.calcite.rel.rules;
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import org.apache.calcite.plan.RelOptRuleCall;
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import org.apache.calcite.plan.RelRule;
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import org.apache.calcite.rel.core.Aggregate;
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import org.apache.calcite.rel.core.AggregateCall;
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import org.apache.calcite.rel.core.Filter;
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import org.apache.calcite.rex.RexNode;
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import org.apache.calcite.tools.RelBuilder;
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import org.immutables.value.Value;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* Rule that converts an aggregate on top of a filter into a filtered aggregate.
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*
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* <p>Before
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* <pre><code>
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* SELECT SUM(salary)
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* FROM Emp
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* WHERE deptno = 10
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* </code></pre>
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*
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* <p>After
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* <pre><code>
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* SELECT SUM(salary) FILTER (WHERE deptno = 10)
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* FROM Emp
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* </code></pre>
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*
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* <p>The transformation is particularly useful in view-based rewriting.
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* The removal of the {@code Filter} operators lifts some restrictions when using
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* the {@link org.apache.calcite.rel.rules.materialize.MaterializedViewRules}.
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*
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* <p>Filtered aggregates can be transformed to other equivalent forms via other
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* transformation rules (e.g., {@link AggregateFilterToCaseRule}).
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*/
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@Value.Enclosing public class AggregateFilterToFilteredAggregateRule
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extends RelRule<AggregateFilterToFilteredAggregateRule.Config> {
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private AggregateFilterToFilteredAggregateRule(Config config) {
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super(config);
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}
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@Override public void onMatch(RelOptRuleCall call) {
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Aggregate aggregate = call.rel(0);
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Filter filter = call.rel(1);
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if (!aggregate.getGroupSet().isEmpty()) {
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// At the moment we only support the transformation for grand totals, i.e.,
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// aggregates with no grouping keys.
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return;
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}
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RelBuilder builder = call.builder();
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builder.push(filter.getInput());
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List<RexNode> projects = new ArrayList<>(builder.fields());
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List<AggregateCall> newAggCalls = new ArrayList<>();
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for (AggregateCall aggCall : aggregate.getAggCallList()) {
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if (!aggCall.getAggregation().allowsFilter()) {
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return;
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}
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RexNode condition = filter.getCondition();
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// If the aggregate call has its own filter, combine it with the filter condition.
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if (aggCall.hasFilter()) {
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condition = builder.and(condition, builder.field(aggCall.filterArg));
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}
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int pos = projects.indexOf(condition);
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if (pos < 0) {
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pos = projects.size();
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projects.add(condition);
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}
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newAggCalls.add(aggCall.withFilter(pos));
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}
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builder.project(projects);
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builder.aggregate(builder.groupKey(), newAggCalls);
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call.transformTo(builder.build());
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}
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/** Rule configuration. */
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@Value.Immutable public interface Config extends RelRule.Config {
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Config DEFAULT = ImmutableAggregateFilterToFilteredAggregateRule.Config.of()
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.withOperandSupplier(
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a -> a.operand(Aggregate.class).oneInput(f -> f.operand(Filter.class).anyInputs()));
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@Override default AggregateFilterToFilteredAggregateRule toRule() {
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return new AggregateFilterToFilteredAggregateRule(this);
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}
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}
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}

‎core/src/main/java/org/apache/calcite/rel/rules/CoreRules.java‎

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public static final AggregateFilterToCaseRule AGGREGATE_FILTER_TO_CASE =
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AggregateFilterToCaseRule.Config.DEFAULT.toRule();
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/** Rule that converts an aggregate on of a filter into a filtered aggregate. */
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public static final AggregateFilterToFilteredAggregateRule
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AGGREGATE_FILTER_TO_FILTERED_AGGREGATE =
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AggregateFilterToFilteredAggregateRule.Config.DEFAULT.toRule();
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/** Rule that remove duplicate {@link Sort} keys. */
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public static final SortRemoveDuplicateKeysRule SORT_REMOVE_DUPLICATE_KEYS =
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SortRemoveDuplicateKeysRule.Config.DEFAULT.toRule();

‎core/src/test/java/org/apache/calcite/test/AggregateFilterToFilteredAggregateRuleTest.java‎

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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to you under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.calcite.test;
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import org.apache.calcite.plan.RelOptRule;
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import org.apache.calcite.plan.hep.HepProgram;
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import org.apache.calcite.rel.rules.AggregateFilterToFilteredAggregateRule;
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import org.apache.calcite.rel.rules.CoreRules;
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import org.junit.jupiter.api.AfterAll;
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import org.junit.jupiter.api.Test;
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import java.util.ArrayList;
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import java.util.List;
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import static org.apache.calcite.rel.rules.CoreRules.AGGREGATE_FILTER_TO_FILTERED_AGGREGATE;
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import static org.apache.calcite.rel.rules.CoreRules.AGGREGATE_PROJECT_MERGE;
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import static org.apache.calcite.rel.rules.CoreRules.PROJECT_FILTER_TRANSPOSE_WHOLE_PROJECT_EXPRESSIONS;
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/**
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* Unit tests for {@link AggregateFilterToFilteredAggregateRule}.
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*
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* <p>Relevant tickets:
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* <ul>
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* <li><a href="https://issues.apache.org/jira/browse/CALCITE-7362">
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* [CALCITE-7362] Add rule to transform WHERE clauses into filtered aggregates
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* </a></li>
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* </ul>
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*/
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class AggregateFilterToFilteredAggregateRuleTest {
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private static RelOptFixture fixture() {
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return RelOptFixture.DEFAULT.withDiffRepos(
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DiffRepository.lookup(AggregateFilterToFilteredAggregateRuleTest.class));
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}
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private static RelOptFixture sql(String sql) {
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return fixture().sql(sql);
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}
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@Test void testSingleColumnAggregate() {
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String sql = "select sum(sal) from emp where deptno = 10";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE).check();
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}
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@Test void testSingleStarAggregate() {
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String sql = "select count(*) from emp where deptno = 10";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE).check();
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}
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@Test void testMultiAggregates() {
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String sql = "select sum(sal), min(sal), max(sal), count(*) from emp where deptno = 10";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE).check();
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}
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@Test void testSingleColumnFilteredAggregate() {
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String sql = "select sum(sal) filter (where ename = 'Bob') from emp where deptno = 10";
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List<RelOptRule> preRules = new ArrayList<>();
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preRules.add(AGGREGATE_PROJECT_MERGE);
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preRules.add(PROJECT_FILTER_TRANSPOSE_WHOLE_PROJECT_EXPRESSIONS);
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sql(sql).withPre(HepProgram.builder().addRuleCollection(preRules).build())
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE,
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CoreRules.PROJECT_MERGE).check();
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}
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@Test void testAggregateNoSupportingFilter() {
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String sql = "select single_value(sal) from emp where deptno = 10";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE)
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.checkUnchanged();
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}
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@Test void testSingleColumnAggregateWithGroupBy() {
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String sql = "select sum(sal) from emp where deptno = 10 group by job";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE)
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.checkUnchanged();
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}
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@Test void testSingleColumnAggregateWithGroupingSets() {
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String sql =
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"select sum(sal) from emp where deptno = 10 group by grouping sets ((job), (ename))";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE)
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.checkUnchanged();
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}
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@Test void testSingleColumnAggregateWithEmptyGroupBy() {
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String sql = "select sum(sal) from emp where deptno = 10 group by ()";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE).check();
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}
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@Test void testSingleColumnAggregateWithEmptyGroupingSets() {
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String sql = "select sum(sal) from emp where deptno = 10 group by grouping sets (())";
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sql(sql).withPreRule(AGGREGATE_PROJECT_MERGE)
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.withRule(AGGREGATE_FILTER_TO_FILTERED_AGGREGATE).check();
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}
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@AfterAll static void checkActualAndReferenceFiles() {
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fixture().diffRepos.checkActualAndReferenceFiles();
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}
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}

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