tanclary commented on code in PR #3367:
URL: https://github.com/apache/calcite/pull/3367#discussion_r1306863310
##########
core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java:
##########
@@ -2699,6 +2699,35 @@ private void
checkPushJoinThroughUnionOnRightDoesNotMatchSemiOrAntiJoin(JoinRelT
.check();
}
+ /** Tests {@link org.apache.calcite.rel.rules.MinusToDistinctRule},
+ * which rewrites an {@link Minus} operator with 3 inputs. */
+ @Test void testMinusToDistinct() {
+ final String sql = "select EMPNO,ENAME,JOB from emp where deptno = 10\n"
+ + "except\n"
+ + "select EMPNO,ENAME,JOB from emp where deptno = 20\n"
+ + "except\n"
+ + "select EMPNO,ENAME,JOB from emp where deptno = 30\n";
+ sql(sql)
+ .withRule(CoreRules.MINUS_MERGE,
+ CoreRules.MINUS_TO_DISTINCT)
+ .check();
+ }
+
+ /** Tests {@link org.apache.calcite.rel.rules.MinusToDistinctRule},
+ * correctly ignores an {@code EXCEPT ALL}. It can only handle
+ * * {@code EXCEPT DISTINCT}.*/
Review Comment:
Is this comment formatted incorrectly? Looks like there is an extra * and
could use a space at the end
##########
core/src/main/java/org/apache/calcite/rel/rules/MinusToDistinctRule.java:
##########
@@ -0,0 +1,179 @@
+/*
+ * 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 org.apache.calcite.rel.rules;
+
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelOptRuleCall;
+import org.apache.calcite.plan.RelRule;
+import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.core.Minus;
+import org.apache.calcite.rel.logical.LogicalMinus;
+import org.apache.calcite.rex.RexBuilder;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.SqlOperator;
+import org.apache.calcite.sql.fun.SqlStdOperatorTable;
+import org.apache.calcite.tools.RelBuilder;
+import org.apache.calcite.tools.RelBuilderFactory;
+import org.apache.calcite.util.ImmutableBitSet;
+import org.apache.calcite.util.Util;
+
+import com.google.common.collect.ImmutableList;
+
+import org.immutables.value.Value;
+
+import java.math.BigDecimal;
+
+/**
+ * Planner rule that translates a distinct
+ * {@link org.apache.calcite.rel.core.Minus}
+ * (<code>all</code> = <code>false</code>)
+ * into a group of operators composed of
+ * {@link org.apache.calcite.rel.core.Union},
+ * {@link org.apache.calcite.rel.core.Aggregate},
+ * {@link org.apache.calcite.rel.core.Filter},etc.
+ *
+ * <p>For example, the query
+
+ * <blockquote><pre>{@code
+ * select a,b from t1
+ * except
+ * select a,b from t2
+ * except
+ * select a,b from t3
+ * }</pre></blockquote>
+ *
+ * <p> will convert to
+ *
+ * <blockquote><pre>{@code
+ * select a,b
+ * from (select a,b,0 as m from t1
+ * union all
+ * select a,b,1 as m from t2
+ * union all
+ * select a,b,2 as m from t3)
+ * group by a,b
+ * having count(*) filter (where m = 0) > 0
+ * and count(*) filter (where m = 1) = 0
+ * and count(*) filter (where m = 2) = 0
+ * }</pre></blockquote>
+ *
+ * @see CoreRules#MINUS_TO_DISTINCT
+ */
[email protected]
+public class MinusToDistinctRule
+ extends RelRule<MinusToDistinctRule.Config>
+ implements TransformationRule {
+
+ protected MinusToDistinctRule(Config config) {
+ super(config);
+ }
+
+ @Deprecated // to be removed before 2.0
+ public MinusToDistinctRule(Class<? extends Minus> minusClass,
+ RelBuilderFactory relBuilderFactory) {
+
this(MinusToDistinctRule.Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
+ .as(MinusToDistinctRule.Config.class)
+ .withOperandFor(minusClass));
+ }
+
+ @Override public void onMatch(RelOptRuleCall call) {
+ Minus minus = call.rel(0);
+
+ if (minus.all) {
+ // Nothing we can do
+ return;
+ }
+
+ final RelOptCluster cluster = minus.getCluster();
+ final RelBuilder relBuilder = call.builder();
+ final RexBuilder rexBuilder = cluster.getRexBuilder();
+ final int branchCount = minus.getInputs().size();
+
+ // For each child branch in minus,add a column which indicates branch index
+ // e.g. select EMPNO from emp -> select EMPNO,0 from emp
+ // 0 indicates that it comes from minus the first child branch
+ for (int i = 0; i < branchCount; i++) {
+ relBuilder.push(minus.getInput(i));
+ relBuilder.projectPlus(relBuilder.literal(new BigDecimal(i)));
+ }
+
+ // create a union above all the branches
+ relBuilder.union(true, branchCount);
+
+ final RelNode union = relBuilder.peek();
+ final int originalFieldCnt = union.getRowType().getFieldCount() - 1;
+
+ ImmutableList.Builder<RexNode> projects = ImmutableList.builder();
+ // skip the branch index column
+ projects.addAll(Util.first(relBuilder.fields(), originalFieldCnt));
+
+ // On top of the Union, add a Project and add branch cnt number boolean
columns
+ // e.g. LogicalProject(EMPNO=[$0], $f1=[=($1, 0)], $f2=[=($1, 1)],
$f3=[=($1, 2)])
+ // $f1,$f2,$f3 are the boolean indicate whether it comes from the
corresponding branch
+ for (int i = 0; i < branchCount; i++) {
+ projects.add(
+ relBuilder.equals(relBuilder.field(originalFieldCnt),
+ relBuilder.literal(new BigDecimal(i))));
+ }
+
+ relBuilder.project(projects.build());
+
+ // Add the count(*) filter $f1(..) for each branch
+ ImmutableList.Builder<RelBuilder.AggCall> aggCalls =
ImmutableList.builder();
+ for (int i = 0; i < branchCount; i++) {
+
aggCalls.add(relBuilder.countStar(null).filter(relBuilder.field(originalFieldCnt
+ i)));
+ }
Review Comment:
Is there anyway to combine these `for` loops? I noticed we iterate through
the branch count multiple times.
##########
core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java:
##########
@@ -2699,6 +2699,35 @@ private void
checkPushJoinThroughUnionOnRightDoesNotMatchSemiOrAntiJoin(JoinRelT
.check();
}
+ /** Tests {@link org.apache.calcite.rel.rules.MinusToDistinctRule},
Review Comment:
+1, also wondering
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