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From "Milosz Tylenda (JIRA)" <j...@apache.org>
Subject [jira] Commented: (OPENJPA-478) contradictory text in manual section 10.2.6. JPQL GROUP BY, HAVING
Date Sun, 08 Jun 2008 08:01:48 GMT

    [ https://issues.apache.org/jira/browse/OPENJPA-478?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12603354#action_12603354
] 

Milosz Tylenda commented on OPENJPA-478:
----------------------------------------

The JPA spec says:

"If there is no GROUP BY clause and the HAVING clause is used, the result is treated as a
single group,
and the select list can only consist of aggregate functions. The use of HAVING in the absence
of
GROUP BY is not required to be supported by an implementation of this speciļ¬cation. Portable
appli-
cations should not rely on HAVING without the use of GROUP BY."

If OpenJPA does not allow HAVING without GROUP BY, the paragraph in question could be changed
to something like:

"OpenJPA requires that if a query declares a HAVING clause, it must also declare a GROUP BY
clause."


> contradictory text in manual section 10.2.6. JPQL GROUP BY, HAVING
> ------------------------------------------------------------------
>
>                 Key: OPENJPA-478
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-478
>             Project: OpenJPA
>          Issue Type: Bug
>          Components: docs
>         Environment: linux, firefox, etc..
>            Reporter: Andy Schlaikjer
>
> In section 10.2.6. JPQL GROUP BY, HAVING (http://openjpa.apache.org/docs/latest/manual/jpa_langref.html#jpa_langref_group)
the last paragraph seems contradictory:
> """
> If there is no GROUP BY clause and the HAVING  clause is used, the result is treated
as a single group, and the select list can only consist of aggregate functions. When a query
declares a HAVING clause, it must always also declare a GROUP BY clause.
> """
> The first sentences seems to imply that a query may incorporate a HAVING clause without
a GROUP BY clause, but the second sentence indicates otherwise.
> Looking at section 10.2.12 JPQL BNF (http://openjpa.apache.org/docs/latest/manual/jpa_langref.html#jpa_langref_bnf),
it seems as though the BNF contradicts the last sentence:
> """
> select_statement ::= select_clause from_clause [where_clause] [groupby_clause] [having_clause]
[orderby_clause]
> """
> otherwise the BNF would be something like this:
> select_statement ::= select_clause from_clause [where_clause] [groupby_clause [having_clause]]
[orderby_clause]

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