wuchong commented on a change in pull request #9331:
[FLINK-13523][table-planner-blink] Verify and correct arithmetic function's
semantic for Blink planner
URL: https://github.com/apache/flink/pull/9331#discussion_r311886806
##########
File path:
flink-table/flink-table-planner-blink/src/main/scala/org/apache/flink/table/planner/plan/rules/logical/SplitAggregateRule.scala
##########
@@ -304,19 +302,22 @@ class SplitAggregateRule extends RelOptRule(
aggGroupCount + index + avgAggCount + 1,
finalAggregate.getRowType)
avgAggCount += 1
- // TODO
+ // Make a guarantee that the final aggregation returns NULL if
underlying count is ZERO.
+ // We use SUM0 for underlying sum, which may run into ZERO / ZERO,
+ // and division by zero exception occurs.
+ // @see Glossary#SQL2011 SQL:2011 Part 2 Section 6.27
val equals = relBuilder.call(
FlinkSqlOperatorTable.EQUALS,
countInputRef,
relBuilder.getRexBuilder.makeBigintLiteral(JBigDecimal.valueOf(0)))
- val falseT = relBuilder.call(FlinkSqlOperatorTable.DIVIDE,
sumInputRef, countInputRef)
- val trueT = relBuilder.cast(
+ val ifTrue = relBuilder.cast(
relBuilder.getRexBuilder.constantNull(),
aggCall.`type`.getSqlTypeName)
+ val ifFalse = relBuilder.call(FlinkSqlOperatorTable.DIVIDE,
sumInputRef, countInputRef)
Review comment:
Thanks. Please rebase master and resolve the conflicts. Others looks good
to me now.
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