[CALCITE-1059] Not valid to convert Aggregate with on empty to empty if its GROUP BY key is empty

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.7.0
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 14/Jan/16 21:08
• Updated: 22/Mar/16 01:18
• Resolved: 22/Jan/16 07:40

Description

It it not valid to convert Aggregate with on empty to empty if its GROUP BY key is empty. Consider the following SQL:

SELECT count(*) FROM emp WHERE FALSE

Even though the input is empty, the output is one row.

Fix affects PruneEmptyRules.AGGREGATE_INSTANCE.

Also, add a RelBuilderFactory argument to all rules in PruneEmptyRules and call RelBuilder.empty rather than LogicalValues.createEmpty.