[CALCITE-675] Enable AggregateProjectMergeRule in standard rule set

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.3.0-incubating
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 08/Apr/15 17:01
• Updated: 27/Feb/24 22:23
• Resolved: 17/Apr/15 19:42

Description

If you have a simple Project that just re-orders or renames fields, or projects a subset, and it is directly beneath an Aggregate, then the Aggregate can be rewritten in terms of the Project's input.

This rule should also apply if the project computes expressions, if those expressions are not used.

This rule will help AggegateJoinTransposeRule apply in more cases. For example, it cannot currently apply to

select distinct dept.deptno from emp join dept using (deptno)

because the join projects 2 columns and the aggregate only uses one.

Issue Links

• is related to: CALCITE-366 Support Aggregate push down in bushy joins
• relates to: CALCITE-676 AssertionError in GROUPING SETS query