[teiid-issues] [JBoss JIRA] (TEIID-3748) Impala translator - SELECT and HAVING statements are translating differently for Case statements
Steven Hawkins (JIRA)
issues at jboss.org
Thu Oct 29 16:25:00 EDT 2015
[ https://issues.jboss.org/browse/TEIID-3748?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Steven Hawkins updated TEIID-3748:
----------------------------------
Fix Version/s: 8.12.2
> Impala translator - SELECT and HAVING statements are translating differently for Case statements
> ------------------------------------------------------------------------------------------------
>
> Key: TEIID-3748
> URL: https://issues.jboss.org/browse/TEIID-3748
> Project: Teiid
> Issue Type: Bug
> Components: JDBC Connector
> Affects Versions: 8.11.4
> Environment: Ubuntu Trusty
> Reporter: Don Krapohl
> Assignee: Steven Hawkins
> Labels: Impala_Translator, Translators
> Fix For: 8.12.2
>
> Attachments: server.log
>
>
> Error from Impala-
> all DISTINCT aggregate functions need to have the same set of parameters as count(DISTINCT (CASE WHEN (secondcol >= 0) THEN 1 ELSE CAST(NULL AS STRING) END))
> deviating function: count(DISTINCT (CASE WHEN (secondcol >= 0) THEN 1 ELSE NULL END))
> Query:
> SELECT user_key, sum(firstcol),count(distinct case when secondcol >= 0 then 1 end)
> FROM sometable
> WHERE customer_key=6
> GROUP BY user_key
> HAVING sum(firstcol)>100
> AND count(distinct case when secondcol >= 0 then 1 end)=0
>
> Query explanation:
> For all users
> Add up values in the firstcol column (integer column)
> count distinct values in secondcol where secondcol value zero or more
> otherwise return null (output is string)
> Translated Teiid query:
> SELECT user_key, SUM(firstcol) as `EXPR_0`, COUNT(DISTINCT (CASE WHEN (secondcol >= 0) THEN '1' ELSE CAST(NULL AS STRING) END)) as `EXPR_1`
> FROM sometable
> WHERE customer_key` = 6
> HAVING (EXPR_0 > 100) AND (COUNT(DISTINCT (CASE WHEN (secondcol >= 0) THEN '1' ELSE NULL END)) = 0))
> Note the difference between the select and having for EXPR_1:
> Select - THEN '1' ELSE CAST(NULL AS STRING) END
> Having - THEN '1' ELSE NULL END
> Impala doesn't accept that these are the same aggregate function. Aliases aren't accepted in the HAVING.
> One further observation- if we swap the translation and write the statement in the select as
> COUNT(DISTINCT (CASE WHEN (secondcol >= 0) THEN '1' *ELSE NULL END*))
> Teiid translates the SELECT to
> COUNT(DISTINCT (CASE WHEN (secondcol >= 0) THEN '1' *ELSE CAST(NULL AS STRING) END*))
> So it always makes these mismatched.
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