Benchao Li created CALCITE-5201:
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Summary: Improve SemiJoinRule to match more cases for semi join
Key: CALCITE-5201
URL: https://issues.apache.org/jira/browse/CALCITE-5201
Project: Calcite
Issue Type: Improvement
Components: core
Affects Versions: 1.30.0
Reporter: Benchao Li
Assignee: Benchao Li
As disscussed in CALCITE-5195, the following SQL cannot be transformed to semi
join:
{code:sql}
select *
from emp
where exists(select * from dept where emp.deptno = dept.deptno and emp.empno =
dept.deptno)
{code}
Currently {{SemiJoinRule}} requires that right child must be an {{Aggregate}},
however, sometimes it's not, e.g. in
[{{RelBuilder}}|https://github.com/apache/calcite/blob/300f5200fe50870da418366613df1cd09921b1b6/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L2241-L2247],
if the group keys are unique, then we'll remove the {{Aggregate}}.
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