[GitHub] [calcite] amaliujia commented on a change in pull request #2437: [CALCITE-4616] AggregateUnionTransposeRule causes row type mismatch when some inputs have unique grouping key (Vladimir Ozerov)

[GitBox <gi...@apache.org>]

amaliujia commented on a change in pull request #2437:
URL: https://github.com/apache/calcite/pull/2437#discussion_r652083038



##########
File path: core/src/main/java/org/apache/calcite/rel/rules/AggregateUnionTransposeRule.java
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@@ -125,30 +125,34 @@ public AggregateUnionTransposeRule(Class<? extends Aggregate> aggregateClass,
       return;
     }
 
-    // create corresponding aggregates on top of each union child
-    final RelBuilder relBuilder = call.builder();
-    int transformCount = 0;
+    boolean hasNonUniqueInputs = false;
     final RelMetadataQuery mq = call.getMetadataQuery();
     for (RelNode input : union.getInputs()) {
       boolean alreadyUnique =
           RelMdUtil.areColumnsDefinitelyUnique(mq, input,
               aggRel.getGroupSet());
 
-      relBuilder.push(input);
       if (!alreadyUnique) {
-        ++transformCount;
-        relBuilder.aggregate(relBuilder.groupKey(aggRel.getGroupSet()),
-            aggRel.getAggCallList());
+        hasNonUniqueInputs = true;
+        break;
       }
     }
 
-    if (transformCount == 0) {
+    if (!hasNonUniqueInputs) {

Review comment:
       Using `hasUniqueKeyInAllInputs` might be better for reading (I was confused on ! + `Non` combination). Basically this says  all inputs must have unique key on the same column otherwise return.




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