Ruben Q L created CALCITE-6087: ---------------------------------- Summary: EnumerableSortedAggregate returns incorrect result when input is empty Key: CALCITE-6087 URL: https://issues.apache.org/jira/browse/CALCITE-6087 Project: Calcite Issue Type: Bug Components: core Affects Versions: 1.35.0 Reporter: Ruben Q L
Performing a MAX on an empty table (or on a table where we apply a filter which does not return any value) shall return NULL, we can verify this with our "standard" {{EnumerableAggregate}} operator: {code:java} @Test void enumerableAggregateOnEmptyInput() { tester(false, new HrSchema()) .query("select max(deptno) as m from emps where deptno>100") .explainContains( "EnumerableAggregate(group=[{}], m=[MAX($1)])\n" + " EnumerableCalc(expr#0..4=[{inputs}], expr#5=[100], expr#6=[>($t1, $t5)], proj#0..4=[{exprs}], $condition=[$t6])\n" + " EnumerableTableScan(table=[[s, emps]])") .returnsOrdered("m=null"); } {code} However, if we use {{Hook.PLANNER}} to force the aggregation to be implemented via {{EnumerableSortedAggregate}} on the same query: {code:java} @Test void enumerableSortedAggregateOnEmptyInput() { tester(false, new HrSchema()) .query("select max(deptno) as m from emps where deptno>100") .withHook(Hook.PLANNER, (Consumer<RelOptPlanner>) planner -> { planner.removeRule(EnumerableRules.ENUMERABLE_AGGREGATE_RULE); planner.addRule(EnumerableRules.ENUMERABLE_SORTED_AGGREGATE_RULE); }) .explainContains( "EnumerableSortedAggregate(group=[{}], m=[MAX($1)])\n" + " EnumerableCalc(expr#0..4=[{inputs}], expr#5=[100], expr#6=[>($t1, $t5)], proj#0..4=[{exprs}], $condition=[$t6])\n" + " EnumerableTableScan(table=[[s, emps]])") .returnsOrdered("m=null"); } {code} It fails, because the EnumerableSortedAggregate returns an empty result set rather than NULL: {noformat} java.lang.AssertionError: Expected: "m=null" but: was "" {noformat} -- This message was sent by Atlassian Jira (v8.20.10#820010)