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https://issues.apache.org/jira/browse/CALCITE-2857?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16787523#comment-16787523
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Vineet Garg commented on CALCITE-2857:
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bq. Agree, either IN or NOT IN, a.k.a semi-join and anti-semi-join
Can a semi-join not have {{>, <}}? e.g. following query could be rewritten into
semi join (LEFT)
{code:sql}
select * from dept where dept.deptno in (select emp.deptno from emp where
emp.job > dept.name) R
{code}
{code:sql}
select * from dept semi join emp on dept.deptno=emp.deptno AND emp.job >
dept.name
{code}
> 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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