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Julian Hyde commented on CALCITE-6020: -------------------------------------- The decision whether to convert {{SUM}} to {{SUM0}} should always take into account whether the group can be empty. If the group can be empty (e.g. in {{{}GROUP BY (){}}}, or in {{GROUP BY k1, k2}} if the argument to {{SUM}} is nullable, or in certain kinds of window) then {{SUM}} cannot safely be converted to {{{}SUM0{}}}, and the config option should not override that. If we add the config option there should be tests for those kinds of things in {{{}RelBuilderTest{}}}. > SqlToRelConverter should not replace windowed SUM with equivalent expression > using SUM0 > --------------------------------------------------------------------------------------- > > Key: CALCITE-6020 > URL: https://issues.apache.org/jira/browse/CALCITE-6020 > Project: Calcite > Issue Type: Improvement > Reporter: Zoltan Haindrich > Assignee: Zoltan Haindrich > Priority: Major > Labels: pull-request-available > > {{SqlToRelConverter}} replaces {{SUM}} with {{SUM0}} around > [here|https://github.com/apache/calcite/blob/e1991e08a225ef08c2402ab35c310d88fff3c222/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java#L5885] > This might have been needed at some point in the past - but I think it will > be better to leave it as {{SUM}} - as in case there is no {{SUM0}} in the > system that will be replaced with a {{COALESCE(SUM(...) , 0 )}} to provide it > - as see > [here|https://github.com/apache/calcite/blob/e1991e08a225ef08c2402ab35c310d88fff3c222/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java#L1288] -- This message was sent by Atlassian Jira (v8.20.10#820010)