Package org.apache.calcite.rel.rules

Class AggregateGroupingSetsToUnionRule

java.lang.Object
org.apache.calcite.plan.RelOptRule
org.apache.calcite.plan.RelRule<AggregateGroupingSetsToUnionRule.Config>
org.apache.calcite.rel.rules.AggregateGroupingSetsToUnionRule
All Implemented Interfaces:
SubstitutionRule, TransformationRule
@Enclosing public class AggregateGroupingSetsToUnionRule extends RelRule<AggregateGroupingSetsToUnionRule.Config> implements SubstitutionRule
Rule that converts a Aggregate with GROUPING SETS into a UNION ALL of simpler aggregates.

Example transformation: 


   SELECT a, b, c FROM t GROUP BY GROUPING SETS ((a,b), (a,c))

Transformed to: 


   SELECT a, b, NULL AS c FROM t GROUP BY a, b
   UNION ALL
   SELECT a, NULL AS b, c FROM t GROUP BY a, c