[ https://issues.apache.org/jira/browse/CALCITE-6201?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jiajun Xie resolved CALCITE-6201. --------------------------------- Resolution: Duplicate > Merge Aggregate node if count distinct column has been deduplicated > ------------------------------------------------------------------- > > Key: CALCITE-6201 > URL: https://issues.apache.org/jira/browse/CALCITE-6201 > Project: Calcite > Issue Type: Improvement > Components: core > Reporter: Jiajun Xie > Assignee: Jiajun Xie > Priority: Minor > > distinct column is redundant because count has distinct. > {code:java} > select count(distinct x) cnt > from( > select distinct sal x from emp > ) t {code} > PlanBefore is > {noformat} > LogicalAggregate(group=[{}], CNT=[COUNT(DISTINCT $0)]) > LogicalAggregate(group=[{5}]) > LogicalTableScan(table=[[CATALOG, SALES, EMP]]){noformat} > PlanAfter should be > {noformat} > LogicalAggregate(group=[{}], CNT=[COUNT(DISTINCT $5)]) > LogicalTableScan(table=[[CATALOG, SALES, EMP]]){noformat} > But `CoreRules.AGGREGATE_MERGE` not support it, we can improve it. > -- This message was sent by Atlassian Jira (v8.20.10#820010)