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作者 A question about find
gaoxt1983





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于 2006-11-08 17:23 user profilesend a private message to usersearch all posts byselect and copy to clipboard. 
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I have three table : table A has many table B, table B has many table C, sometimes , I want to find all A 's data , and each A's row , I want to find all the B which meet the condition, which is a iteration. But my companymates warning me not to do that, because of effective. I should do that :
select max(a.position_name) as pn, max(c.name) as dn,
count(*) as c from position a, resume b, department c
where a.id = b.position_id and a.department_id = c.id
group by b.position_id

I think this method is sick , but I don't know better, would anyone help me?


why edited on 2006-11-08 19:24

作者 Re:A question about find [Re:gaoxt1983]
why

問題兒童

总版主


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于 2006-11-08 19:26 user profilesend a private message to usersend email to whysearch all posts byselect and copy to clipboard. 
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Your mate are right, avoid cursor (iteration) for RDBMS whenever possible.


作者 Re:A question about find [Re:gaoxt1983]
gaoxt1983





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于 2006-11-08 21:45 user profilesend a private message to usersearch all posts byselect and copy to clipboard. 
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yep, I know that , but the sql make me sick , would you help me improve it ?
PS:how to do this in Hibernate?



作者 Re:A question about find [Re:gaoxt1983]
why

問題兒童

总版主


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于 2006-11-09 07:05 user profilesend a private message to usersend email to whysearch all posts byselect and copy to clipboard. 
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If this really make you sick, then you'd better stay away from SQL.



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