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https://issues.apache.org/jira/browse/TRAFODION-2047?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15399376#comment-15399376
 ] 

ASF GitHub Bot commented on TRAFODION-2047:
-------------------------------------------

Github user traflm commented on a diff in the pull request:

    https://github.com/apache/incubator-trafodion/pull/623#discussion_r72796626
  
    --- Diff: core/sql/optimizer/BindRelExpr.cpp ---
    @@ -717,7 +717,7 @@ static ItemExpr *intersectColumns(const RETDesc 
&leftTable,
         ItemExpr *leftExpr  = leftTable.getValueId(i).getItemExpr();
         ItemExpr *rightExpr = rightTable.getValueId(i).getItemExpr();
         BiRelat *compare = new (bindWA->wHeap())
    -      BiRelat(ITM_EQUAL, leftExpr, rightExpr);
    +      BiRelat(ITM_EQUAL, leftExpr, rightExpr, TRUE);
    --- End diff --
    
    the showplan output is too long. not sure if you can see it correctly... 
Here is simpler version of explain, it is a nest loop join. 
    
    >>explain options 'f' select eno, ename, dno from t021
     intersect
    +>+>select eno, ename, dno from t022;
    
    LC   RC   OP   OPERATOR              OPT       DESCRIPTION           CARD
    ---- ---- ---- --------------------  --------  --------------------  
---------
    
    4    .    5    root                                                  
2.00E+000
    2    3    4    nested_join                                           
2.00E+000
    .    .    3    trafodion_vsbb_scan             T021                  
1.00E+000
    1    .    2    hash_groupby                                          
2.00E+000
    .    .    1    trafodion_scan                  T022                  
2.50E+001



> add SQL syntax support to INTERSECT
> -----------------------------------
>
>                 Key: TRAFODION-2047
>                 URL: https://issues.apache.org/jira/browse/TRAFODION-2047
>             Project: Apache Trafodion
>          Issue Type: New Feature
>            Reporter: liu ming
>            Assignee: liu ming
>             Fix For: 2.1-incubating
>
>
> INTERSECT is a common SQL syntax. 
> Trafodion should support it.



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