p = Person.find_by_id(1, :include => :bags, :conditions => ['bag.id in (?), [3,4])
I would like to know how I could make sure this query will only be valid if both 'items.id' '3' & '4' are present rather than '3' or/and '4'.
Thanks
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Please explain a bit more what you're trying to accomplish.Jacob Relkin– Jacob Relkin2010-10-15 05:54:25 +00:00Commented Oct 15, 2010 at 5:54
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In Plain SGL : SELECT * FROM persons p INNER JOIN bags_persons b1 ON b1.person_id = p.id INNER JOIN bags_persons b2 ON b2.person_id = p.id WHERE b1.bag_id = 3 AND b2.bag_id = 4 The point is you need to join 2 times in order to search for both bags at the same time. Maybe there is a neater way to write it in rails, but with :joins and :conditions you'll be able to translate this query into the find syntax.giraff– giraff2010-10-15 07:00:39 +00:00Commented Oct 15, 2010 at 7:00
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Btw, :include is mainly used to prefetch the bags in the resulting person Object, so if you don't access the bags of it after this request :joins will be enough.giraff– giraff2010-10-15 07:04:22 +00:00Commented Oct 15, 2010 at 7:04
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What's the setup? person has_many :bags and bag belongs_to person?marko– marko2010-10-15 10:29:06 +00:00Commented Oct 15, 2010 at 10:29
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@jacob I am trying to run a single query that will return the person only if they have the associated bags. @marko The setup is "person has_many :persons_bags, has_many :bags, :through => :peoples_bags", "peoples_bag belongs_to :person, belongs_to :bag", and "bags has_many :peoples_bag"Joey– Joey2010-10-16 20:58:25 +00:00Commented Oct 16, 2010 at 20:58
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1 Answer
You need to manually construct your 2 inner joins to the bags_persons table:
Person.find_by_id(1, :joins => "INNER JOIN bags_persons bp1 ON bp1.person_id=persons.id INNER JOIN bags_persons bp2 ON bp2.person_id=persons.id", :conditions => "bp1.bag_id=3 AND bp2.bag_id=4")
Hope this helps
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