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Jpql - order by sum ??? [message #556047]

Mon, 30 August 2010 16:29

No real name

Messages: 3
Registered: August 2010

Junior Member

MYSQL
JAVA EE 6
JPA 2

Hello,
i want get a list of "Video Objects" from DB order by Desc how much(good) they are rated.

VideoRatingEntity
@ManyToOne()
@JoinColumn(name = "VIDEO_ID")
videoEntity

ID | VIDEO_ID| USER_ID| RATING
--------------------------------

Video Entity
@OneToMany
videoRatingEntities

ID | ... | ... |
-------------

My Try:
"SELECT v, sum(vrr) "
+ " FROM VideoEntity AS v"
+ " JOIN v.videoRatingEntities AS vr"
+ " JOIN vr.rating AS vrr"
+ " GROUP BY v"
+ " ORDER BY sum(vrr) DESC";

EXCEPTION:
SCHWERWIEGEND: java.lang.IllegalArgumentException: An exception occurred while creating a query in EntityManager:
Exception Description: Syntax error parsing the query [SELECT v, sum(vrr) FROM VideoEntity AS v JOIN v.videoRatingEntities AS vr JOIN vr.rating AS vrr GROUP BY v ORDER BY sum(vrr) DESC].
Internal Exception: org.eclipse.persistence.internal.libraries.antlr.runtime.Ear lyExitException

Hope someone can help.

[Updated on: Mon, 30 August 2010 16:37]

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Re: Jpql - order by sum ??? [message #556079 is a reply to message #556047]

Mon, 30 August 2010 17:54

James Sutherland

Messages: 1939
Registered: July 2009
Location: Ottawa, Canada

Senior Member

>> sum(vrr)

does not make sense, you cannot sum an Entity, it must be a basic value. .i.e sum(vrr.some_value).

What version of EclipseLink are you using? JPQL has been improved in 2.1, but you still cannot sum an Entity.

James : Wiki : Book : Blog : Twitter

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Re: Jpql - order by sum ??? [message #556098 is a reply to message #556047]

Mon, 30 August 2010 19:00

No real name

Messages: 3
Registered: August 2010

Junior Member

I use jpa 2.0

-------------------

vr.rating AS vrr"

rating is a value of the VideoRatingEntity Table, maybe bad definition Smile

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Re: Jpql - order by sum ??? [message #556363 is a reply to message #556047]

Wed, 01 September 2010 00:48

No real name

Messages: 3
Registered: August 2010

Junior Member

But i "improved" my solution:

SELECT video, sum(videoRatings.rating) as sumRating
FROM VideoEntity video
INNER JOIN video.videoRatingEntities as videoRatings
GROUP BY video
ORDER BY sumRating desc

The Problem is that i dont get an lit auf Entities, bec. i have not a unique Select object attribut. But dont know how i can Order By sum and get a list of objects

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