[jira] [Work logged] (HIVE-25209) SELECT query with SUM function producing unexpected result

[ASF GitHub Bot (Jira)]

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https://issues.apache.org/jira/browse/HIVE-25209?focusedWorklogId=613094&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-613094
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ASF GitHub Bot logged work on HIVE-25209:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 22/Jun/21 07:46
            Start Date: 22/Jun/21 07:46
    Worklog Time Spent: 10m 
      Work Description: kgyrtkirk commented on a change in pull request #2360:
URL: https://github.com/apache/hive/pull/2360#discussion_r655492864



##########
File path: ql/src/test/queries/clientpositive/select_sum.q
##########
@@ -0,0 +1,14 @@
+DROP DATABASE IF EXISTS db5 CASCADE;
+CREATE DATABASE db5;
+use db5;
+CREATE TABLE IF NOT EXISTS t1(c0 boolean, c1 boolean);
+
+SELECT SUM(1) FROM t1;

Review comment:
       could you please add an explain to see the optimization in action?

##########
File path: ql/src/test/queries/clientpositive/select_sum.q
##########
@@ -0,0 +1,14 @@
+DROP DATABASE IF EXISTS db5 CASCADE;
+CREATE DATABASE db5;
+use db5;

Review comment:
       these lines could be removed




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Issue Time Tracking
-------------------

    Worklog Id:     (was: 613094)
    Time Spent: 0.5h  (was: 20m)

> SELECT query with SUM function producing unexpected result
> ----------------------------------------------------------
>
>                 Key: HIVE-25209
>                 URL: https://issues.apache.org/jira/browse/HIVE-25209
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Soumyakanti Das
>            Assignee: Soumyakanti Das
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 0.5h
>  Remaining Estimate: 0h
>
> Hive: SELECT query with SUM function producing unexpected result
> Problem Statement:
> {noformat}
> SELECT SUM(1) FROM t1;
> ---- result: 0
> SELECT SUM(agg0) FROM (
>     SELECT SUM(1) as agg0 FROM t1 WHERE t1.c0 UNION ALL 
>     SELECT SUM(1) as agg0 FROM t1 WHERE NOT (t1.c0) UNION ALL 
>     SELECT SUM(1) as agg0 FROM t1 WHERE (t1.c0) IS NULL
>     ) as asdf;
> ---- result: null {noformat}
> Steps to reproduce:
> {noformat}
> DROP DATABASE IF EXISTS db5 CASCADE;
> CREATE DATABASE db5;
> use db5;
> CREATE TABLE IF NOT EXISTS t1(c0 boolean, c1 boolean);
> SELECT SUM(1) FROM t1;
> -- result: 0
> SELECT SUM(agg0) FROM (
>     SELECT SUM(1) as agg0 FROM t1 WHERE t1.c0 UNION ALL 
>     SELECT SUM(1) as agg0 FROM t1 WHERE NOT (t1.c0) UNION ALL 
>     SELECT SUM(1) as agg0 FROM t1 WHERE (t1.c0) IS NULL
>     ) as asdf;
> -- result: null {noformat}
> Observations:
> SELECT SUM(1) as agg0 FROM t1 WHERE t1.c0 = t1.c1; – will result in null
> Similarity with postgres, 
>  both the queries result in null
> Similarity with Impala,
>  both the queries result in null



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