Calcite LogicalAggregate

Question

What is a proper way to associate an AggregateCall that is part of a HAVING expression with a corresponding field in a RelRecordType for the LogicalAggregate? If the AggregateCall is not part of the SELECT clause, the LogicalAggregate's RelRecordType still has it, but the AggregateCall's name attribute is set to NULL and RelRecordType.getField(AggregateCall.getName()) can't be used in this case. If the AggregateCall is a part of the final output, its name is set and RelRecordType.getField(AggregateCall.getName()) returns the right field.

Answer 1

Use field ordinals rather than names.

In the world of Calcite RelNodes and RexNodes, field names are not that important; they exist mainly to help you understand the purpose of fields when debugging. Names of AggregateCalls are even less important; they exist so that Aggregate can give reasonable names to its fields, and if they don't exist, that's fine.

If your SELECT has N fields (numbered 0 .. N-1) and a HAVING clause, you will likely add the HAVING predicate as field N, apply a Filter relational operator, then apply a Project so that only fields 0 .. N-1 are returned. I'm pretty sure that this is what SqlToRelConverter does already.