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https://issues.apache.org/jira/browse/CALCITE-2857?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16790152#comment-16790152
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Haisheng Yuan commented on CALCITE-2857:
----------------------------------------
A simpler repro query would be:
{code:sql}
select * from dept where exists (select * from emp where emp.deptno <>
dept.deptno)
{code}
We got an initial logic plan:
{code:java}
LogicalProject(DEPTNO=[$0], NAME=[$1])
LogicalProject(DEPTNO=[$0], NAME=[$1], DEPTNO0=[CAST($2):INTEGER],
$f1=[CAST($3):BOOLEAN])
LogicalJoin(condition=[=($0, $2)], joinType=[inner])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
LogicalAggregate(group=[{0}], agg#0=[MIN($1)])
LogicalProject(DEPTNO0=[$9], $f0=[true])
LogicalJoin(condition=[<>($7, $9)], joinType=[inner])
LogicalTableScan(table=[[CATALOG, SALES, EMP]])
LogicalProject(DEPTNO=[$0])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
{code}
Which is indeed complicated.
> SemiJoin extends Join directly instead of EquiJoin to support non-equi
> condition
> --------------------------------------------------------------------------------
>
> Key: CALCITE-2857
> URL: https://issues.apache.org/jira/browse/CALCITE-2857
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: godfrey he
> Priority: Major
>
> SemiJoin extends Join directly instead of EquiJoin to support non-equi
> condition,
> e.g.
> {code:sql}
> select * from (select * from dept where dept.deptno in (select emp.deptno
> from emp where emp.job <> dept.name))R where R.deptno <= 10
> {code}
> Currently, this query will be converted to
> {code}
> SemiJoin(condition=[AND(=($1, $3), =($0, $2))], joinType=[inner])
> LogicalFilter(condition=[<=($0, 10)])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> LogicalProject(DEPTNO=[$7], NAME=[$9])
> LogicalJoin(condition=[<>($2, $9)], joinType=[inner])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> LogicalAggregate(group=[{0}])
> LogicalProject(NAME=[$1])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> {code}
> however the following plan is more efficient than the above one:
> {code}
> LogicalProject(DEPTNO=[$0], NAME=[$1])
> LogicalFilter(condition=[<=($0, 10)])
> SemiJoin(condition=[=AND(=($0, $3), <>($1, $2))], joinType=[inner])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> LogicalProject(JOB=[$2], DEPTNO=[$7])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> {code}
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