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Julian Hyde resolved CALCITE-2195. ---------------------------------- Resolution: Fixed Fixed in [73a09a69|http://git-wip-us.apache.org/repos/asf/calcite/commit/73a09a69]; thanks for the PR, [~zhong.j.yu]! > AggregateJoinTransposeRule fails to aggregate over unique column > ---------------------------------------------------------------- > > Key: CALCITE-2195 > URL: https://issues.apache.org/jira/browse/CALCITE-2195 > Project: Calcite > Issue Type: Bug > Components: core > Affects Versions: 1.15.0 > Reporter: Zhong Yu > Assignee: Julian Hyde > Priority: Major > Fix For: 1.16.0 > > > The following query, in which "A.sal" is unique, > {code:java} > select sum(A.sal) > from (select distinct sal from sales.emp) as A > join sales.emp as B on A.sal=B.sal > {code} > causes AggregateJoinTransposeRule to fail with message > {code:java} > java.lang.AssertionError: type mismatch: > aggCall type: > INTEGER > inferred type: > BIGINT > {code} > Apparently, this is a bug in the rule when `unique` is true on the A side, in > which case the rule does not aggregate on the A side, `leftSubTotal==null`, > causing `splitter.topSplit()` to only sum over `count()` coming from the B > side. > A solution would be to introduce `splitter.singleton()` on the A side, so > that it can be fed to topSplit() to be multiplied by the count. > In the case that the `unique` side does not contain the column of an agg > call, it seems that we should do `other_singleton()` on this side, and feed > it to topSplit(). However, realize that the `other()` expression is > necessarily a `count()`, or a scalar function of `count()`, because it does > not depend on any column values. In the same way, the proposed > `other_singleton()` necessarily returns 1, or some constant value. > `topSplit()` would not have any need of that constant value.Therefore in this > case, we don't need a split on this side, just leave its subtotal as null. > > I'm working on a pull-request based on these understandings. BTW, is there a > reference to the algorithm used in the code? I can only find some old papers > that don't exactly cover the logic of the code. Thanks. -- This message was sent by Atlassian JIRA (v7.6.3#76005)