julianhyde commented on code in PR #4495:
URL: https://github.com/apache/calcite/pull/4495#discussion_r2264077930
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core/src/main/java/org/apache/calcite/tools/RelBuilder.java:
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@@ -2819,28 +2819,56 @@ private RelBuilder aggregate_(ImmutableBitSet groupSet,
* GROUP_ID returns wrong result</a> and
* <a
href="https://issues.apache.org/jira/browse/CALCITE-4748";>[CALCITE-4748]
* If there are duplicate GROUPING SETS, Calcite should return duplicate
- * rows</a>.
+ * rows</a> and
+ * <a
href="https://issues.apache.org/jira/browse/CALCITE-7126";>[CALCITE-7126]
+ * The calculation result of grouping function is wrong</a>.
*/
private RelBuilder rewriteAggregateWithDuplicateGroupSets(
ImmutableBitSet groupSet,
ImmutableSortedMultiset<ImmutableBitSet> groupSets,
List<AggCallPlus> aggregateCalls) {
+ List<AggregateCall> calls =
+ aggregateCalls.stream()
+ .map(AggCallPlus::aggregateCall)
+ .collect(Collectors.toList());
+ return rewriteAggregateWithDuplicateGroupSetsImpl(groupSet, groupSets,
calls);
+ }
+
+ private RelBuilder rewriteAggregateWithDuplicateGroupSetsImpl(
+ ImmutableBitSet groupSet,
+ ImmutableSortedMultiset<ImmutableBitSet> groupSets,
+ List<AggregateCall> aggregateCalls) {
+ final int groupCount = groupSet.cardinality();
+ // No need to handle the case without GROUP BY in aggregate.
+ if (groupCount > 0) {
+ aggregateCalls = aggregateCalls.stream()
+ .map(c -> c.withAllowChangeNullable(false))
+ .collect(Collectors.toList());
+ }
+
final List<String> fieldNamesIfNoRewrite =
- Aggregate.deriveRowType(getTypeFactory(), peek().getRowType(), false,
- groupSet, groupSets.asList(),
- aggregateCalls.stream().map(AggCallPlus::aggregateCall)
- .collect(toImmutableList())).getFieldNames();
-
- // If n duplicates exist for a particular grouping, the {@code GROUP_ID()}
- // function produces values in the range 0 to n-1. For each value,
- // we need to figure out the corresponding group sets.
- //
- // For example, "... GROUPING SETS (a, a, b, c, c, c, c)"
- // (i) The max value of the GROUP_ID() function returns is 3
- // (ii) GROUPING SETS (a, b, c) produces value 0,
- // GROUPING SETS (a, c) produces value 1,
- // GROUPING SETS (c) produces value 2
- // GROUPING SETS (c) produces value 3
+ Aggregate.deriveRowType(getTypeFactory(), peek().getRowType(),
Review Comment:
A pretty good comment,
```
If n duplicates exist for a particular grouping, the {@code GROUP_ID()}
// function produces values in the range 0 to n-1. For each value,
// we need to figure out the corresponding group sets.
//
// For example, "... GROUPING SETS (a, a, b, c, c, c, c)"
// (i) The max value of the GROUP_ID() function returns is 3
// (ii) GROUPING SETS (a, b, c) produces value 0,
// GROUPING SETS (a, c) produces value 1,
// GROUPING SETS (c) produces value 2
// GROUPING SETS (c) produces value 3
```
has been removed. This is tricky code, we need more comments not fewer.
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