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jguidos
 Post subject: [newbie] Self Join in HQL?
PostPosted: Sat Jan 10, 2004 10:13 pm 
Newbie

Joined: Sat Jan 10, 2004 10:06 pm
Posts: 9
Location: Calgary, AB, Canada
Hi All,

OK I wish to write a bit of HQL to detect, say, all Cats who are more than 2 years apart in age. In SQL thats an easy self join, but as far as I can see in HQL you can't self join unless a pre-existing relationship has been set up in the mappings for the Cat class.

So, how would I write a self join HQL query without such a relationship? Who cares about cats that are more than two years apart in age? I don't like cats.... ;-)

Jay
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gavin
 Post subject:
PostPosted: Sat Jan 10, 2004 10:36 pm 
Hibernate Team
Hibernate Team

Joined: Tue Aug 26, 2003 12:50 pm
Posts: 5130
Location: Melbourne, Australia
Code:
from Cat older, Cat younger where older.age - younger.age > 2
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jguidos
 Post subject:
PostPosted: Sat Jan 10, 2004 11:17 pm 
Newbie

Joined: Sat Jan 10, 2004 10:06 pm
Posts: 9
Location: Calgary, AB, Canada
gavin wrote:
Code:
from Cat older, Cat younger where older.age - younger.age > 2


Cool! Thanks Gavin, I tried something like that but must of screwed up the syntax a bit cuz I got an error message

J
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wrapper
 Post subject:
PostPosted: Mon Jul 12, 2004 10:18 am 
Newbie

Joined: Fri Jul 09, 2004 11:49 am
Posts: 1
I ask in this topic because my question is rather similar.

gavin wrote:
Code:
from Cat older, Cat younger where older.age - younger.age > 2


Doing like this i have inner join, and when there is no local translations i get 0 rows.

Code:
"select base, local from Translation base, Translation local
where base.lang = :baseLang
and local.lang = :localLang
and base.entry = local.entry"


i need smth like:

Code:
select base, local from Translation base left outer join Translation local


but I get exception: outer or full join must be followed by path expression

So, how can I implement self left join?
Thanks.
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junkie1211
 Post subject: Self Outer Join
PostPosted: Sat Mar 11, 2006 4:19 am 
Newbie

Joined: Sat Mar 11, 2006 4:15 am
Posts: 1
Hi
I am facing same problem. How can we implement [b]self outer join[/b] in hibernate.

Please help
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david
 Post subject:
PostPosted: Sat Mar 11, 2006 9:04 pm 
Hibernate Team
Hibernate Team

Joined: Tue Aug 26, 2003 7:19 pm
Posts: 2364
Location: Brisbane, Australia
In HQL you require the relationship to be mapped for out join. Use native SQL query.
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