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https://issues.apache.org/jira/browse/CALCITE-41?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Hyde resolved CALCITE-41.
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Resolution: Duplicate
Fix Version/s: 0.9.0-incubating
> Add rule to propagate constraints onto aliased columns
> ------------------------------------------------------
>
> Key: CALCITE-41
> URL: https://issues.apache.org/jira/browse/CALCITE-41
> Project: Calcite
> Issue Type: Bug
> Reporter: GitHub Import
> Assignee: Julian Hyde
> Labels: github-import
> Fix For: 0.9.0-incubating
>
>
> Consider:
> SELECT *
> FROM emp JOIN dept ON emp.deptno = dept.deptno
> WHERE emp.deptno = 10
> Clearly we can push down "emp.deptno = 10" through the join. But we can also
> generate a constraint "dept.deptno = 10" on the other input to the join. This
> task is to add a rule to achieve that.
> The rule would propagate the constraints on column "a" onto column "b" when
> "a" and "b" are compared using "=" or other relational operator (e.g. ">") in
> a filter or join condition.
> The planner state should reflect the fact that such constraints are optional
> -- i.e. the query produces the same result if the constraints are omitted --
> and therefore the constraints can be omitted if they turn out to be expensive
> to implement.
> ---------------- Imported from GitHub ----------------
> Url: https://github.com/julianhyde/optiq/issues/41
> Created by: [julianhyde|https://github.com/julianhyde]
> Labels:
> Created at: Fri May 17 01:13:26 CEST 2013
> State: open
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