ccaominh commented on a change in pull request #9122: Add SQL GROUPING SETS
support.
URL: https://github.com/apache/druid/pull/9122#discussion_r384192373
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File path: sql/src/main/java/org/apache/druid/sql/calcite/rel/Grouping.java
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@@ -141,36 +159,95 @@ public RowSignature getOutputRowSignature()
return outputRowSignature;
}
+ /**
+ * Applies a post-grouping projection.
+ *
+ * @see DruidQuery#computeGrouping which uses this
+ */
+ public Grouping applyProject(final PlannerContext plannerContext, final
Project project)
+ {
+ final List<DimensionExpression> newDimensions = new ArrayList<>();
+ final List<Aggregation> newAggregations = new ArrayList<>(aggregations);
+ final Subtotals newSubtotals;
+
+ final Projection postAggregationProjection = Projection.postAggregation(
+ project,
+ plannerContext,
+ outputRowSignature,
+ "p"
+ );
+
+ postAggregationProjection.getPostAggregators().forEach(
+ postAggregator ->
newAggregations.add(Aggregation.create(postAggregator))
+ );
+
+ // Remove literal dimensions that did not appear in the projection. This
is useful for queries
+ // like "SELECT COUNT(*) FROM tbl GROUP BY 'dummy'" which some tools can
generate, and for which we don't
+ // actually want to include a dimension 'dummy'.
+ final ImmutableBitSet aggregateProjectBits =
RelOptUtil.InputFinder.bits(project.getChildExps(), null);
+ final int[] newDimIndexes = new int[dimensions.size()];
+
+ for (int i = 0; i < dimensions.size(); i++) {
+ final DimensionExpression dimension = dimensions.get(i);
+ if (Parser.parse(dimension.getDruidExpression().getExpression(),
plannerContext.getExprMacroTable())
+ .isLiteral() && !aggregateProjectBits.get(i)) {
+ newDimIndexes[i] = -1;
+ } else {
+ newDimIndexes[i] = newDimensions.size();
+ newDimensions.add(dimension);
+ }
+ }
+
+ // Renumber subtotals, if needed, to account for removed dummy dimensions.
+ if (newDimensions.size() != dimensions.size()) {
+ final List<IntList> newSubtotalsList = new ArrayList<>();
+
+ for (IntList subtotal : subtotals.getSubtotals()) {
+ final IntList newSubtotal = new IntArrayList();
+ for (int dimIndex : subtotal) {
+ final int newDimIndex = newDimIndexes[dimIndex];
+ if (newDimIndex >= 0) {
+ newSubtotal.add(newDimIndex);
+ }
+ }
+
+ newSubtotalsList.add(newSubtotal);
+ }
+
+ newSubtotals = new Subtotals(newSubtotalsList);
+ } else {
+ newSubtotals = subtotals;
+ }
+
+ return Grouping.create(
+ newDimensions,
+ newSubtotals,
+ newAggregations,
+ havingFilter,
+ postAggregationProjection.getOutputRowSignature()
+ );
+ }
+
@Override
- public boolean equals(final Object o)
+ public boolean equals(Object o)
Review comment:
Is there a test for this?
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