Class AggregateProjectConstantToDummyJoinRule

@Enclosing public final class AggregateProjectConstantToDummyJoinRule extends RelRule<AggregateProjectConstantToDummyJoinRule.Config>
Planner rule that recognizes a Aggregate on top of a Project where the aggregate's group set contains literals (true, false, DATE, chars, etc), and removes the literals from the group keys by joining with a dummy table of literals.

 select avg(sal)
 from emp
 group by true, DATE '2022-01-01';

 select avg(sal)
 from emp, (select true x, DATE '2022-01-01' d) dummy
 group by dummy.x, dummy.d;