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https://issues.apache.org/jira/browse/CALCITE-6948?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17943403#comment-17943403
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Zhen Chen commented on CALCITE-6948:
------------------------------------
Thank you very much to [~mbudiu] and [~julianhyde] for giving me great
suggestions. Currently only EXCEPT is supported, EXCEPT ALL is not supported.
Can support 2-way minus, rules can be repeated conversion plan to achieve
multiple. {{IS NOT DISTINCT FROM}} can be converted to '{{{}='{}}} when the
types are not nullable, I will modify here. Thanks!
> Implement MinusToAntiJoinRule
> -----------------------------
>
> Key: CALCITE-6948
> URL: https://issues.apache.org/jira/browse/CALCITE-6948
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.39.0
> Reporter: Zhen Chen
> Assignee: Zhen Chen
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.40.0
>
>
> Similar to IntersectToSemiJoinRule, we can implement MinusToAntiJoinRule.
> Like this:
> from:
> {code:java}
> LogicalMinus(all=[false])
> LogicalProject(ENAME=[$1])
> LogicalFilter(condition=[=($7, 10)])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> LogicalProject(ENAME=[$1])
> LogicalFilter(condition=[=($7, 20)])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]]) {code}
> to:
> {code:java}
> LogicalAggregate(group=[{0}])
> LogicalJoin(condition=[IS NOT DISTINCT FROM($0, $1)], joinType=[anti])
> LogicalProject(ENAME=[$1])
> LogicalFilter(condition=[=($7, 10)])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> LogicalProject(ENAME=[$1])
> LogicalFilter(condition=[=($7, 20)])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]]) {code}
> SQL like:
> from
>
> {code:java}
> select empid from emps
> except
> select empid from emps where empid > 150;{code}
> to
>
> {code:java}
> SELECT empid
> FROM emps A
> WHERE NOT EXISTS (
> SELECT 1
> FROM emps B
> WHERE B.empid > 150 and A.empid is not distinct from B.empid
> ); {code}
>
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