Hello,
I am looking for a join query between 3 tables that will give me the
results I''m looking for.
I have a properties tables that has many layouts and many photos as
well. The layouts table can also, have many layouts. When I run the
query, I want to show a list of properties w/ one main photo from the
photos table, and a list of layouts per property. Right now, the query
I have will show a list of properties, but properties will be displayed
multiple times if there are more than one photos. Here''s my current
query in rails form:
[code]
@properties = Property.paginate(:page => params[:page],
:select => ["properties.*,
layouts.*, photos.*"],
:joins => ["INNER JOIN layouts
ON layouts.property_id = properties.property_id LEFT JOIN photos ON
photos.property_id = properties.property_id"],
:per_page => 20)
[/code]
or, in raw sql:
[code]
SELECT properties.*, layouts.*, photos.photo_file_name FROM `properties`
INNER JOIN layouts ON layouts.property_id = properties.property_id LEFT
JOIN photos ON photos.property_id = properties.property_id WHERE
(properties.property_status=''available'') ORDER BY layouts.rent
LIMIT 20
OFFSET 0
[/code]
Any help would be greatly appreciated!
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On Mon, Jan 23, 2012 at 8:39 PM, Clem Rock <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Hello, > I am looking for a join query between 3 tables that will give me the > results I''m looking for. > > I have a properties tables that has many layouts and many photos as > well. The layouts table can also, have many layouts.Is this a correct statement or a typo? "The layouts table can also, have many layouts."> When I run the > query, I want to show a list of properties w/ one main photo from the > photos table, and a list of layouts per property. Right now, the query > I have will show a list of properties, but properties will be displayed > multiple times if there are more than one photos. Here''s my current > query in rails form: > > [code] > @properties = Property.paginate(:page => params[:page], > :select => ["properties.*, > layouts.*, photos.*"], > :joins => ["INNER JOIN layouts > ON layouts.property_id = properties.property_id LEFT JOIN photos ON > photos.property_id = properties.property_id"], > :per_page => 20) > [/code] > > or, in raw sql: > > [code] > SELECT properties.*, layouts.*, photos.photo_file_name FROM `properties` > INNER JOIN layouts ON layouts.property_id = properties.property_id LEFT > JOIN photos ON photos.property_id = properties.property_id WHERE > (properties.property_status=''available'') ORDER BY layouts.rent LIMIT 20 > OFFSET 0 > [/code] >Which paginator are you using? Which version of Rails? Taking abstraction of the effect the paginator may have ... Look in http://guides.rubyonrails.org/active_record_querying.html Start with the simplest cases in `rails console` and build up your query. Probably a style of @properties = Property.includes(:photos). includes(:layouts). where("properties.property_status=''available''"). order("layouts.rent"). all will get you close (or maybe .joins(layouts) if you really need the INNER JOIN on layouts). Try a solution where you do _not_ set the select manually first. By the design of SQL querying language, the raw SQL will always return the property for each photo (if it is all executed in 1 SQL query). But Activerecord will consolidate the different returned records in 1 record in the @properties list (which then will :have_many photos). HTH, Peter -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
Peter - big thanks for your help. You were right - I meant to say
"the layouts table can have many photos"
Looks like this was the winner for me:
@properties = Property.paginate(:page => params[:page], :per_page =>
20).includes(:photos).includes(:layouts).order("properties.modify_date,
layouts.modify_date").all
Cheers!
Peter Vandenabeele wrote in post #1042203:> On Mon, Jan 23, 2012 at 8:39 PM, Clem Rock
<lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:
>
>> Hello,
>> I am looking for a join query between 3 tables that will give me the
>> results I''m looking for.
>>
>> I have a properties tables that has many layouts and many photos as
>> well. The layouts table can also, have many layouts.
>
>
> Is this a correct statement or a typo? "The layouts table can also,
have
> many layouts."
>
>
>
>> layouts.*, photos.*"],
>> INNER JOIN layouts ON layouts.property_id = properties.property_id LEFT
>> JOIN photos ON photos.property_id = properties.property_id WHERE
>> (properties.property_status=''available'') ORDER BY
layouts.rent LIMIT 20
>> OFFSET 0
>> [/code]
>>
>
> Which paginator are you using?
> Which version of Rails?
>
> Taking abstraction of the effect the paginator may have ...
>
> Look in http://guides.rubyonrails.org/active_record_querying.html
>
> Start with the simplest cases in `rails console` and build up your
> query.
>
> Probably a style of
>
> @properties = Property.includes(:photos).
> includes(:layouts).
>
>
where("properties.property_status=''available''").
> order("layouts.rent").
> all
>
> will get you close (or maybe .joins(layouts) if you really need the
> INNER
> JOIN
> on layouts).
>
> Try a solution where you do _not_ set the select manually first.
>
> By the design of SQL querying language, the raw SQL will always return
> the property for each photo (if it is all executed in 1 SQL query).
> But Activerecord will consolidate the different returned records in 1
> record
> in the @properties list (which then will :have_many photos).
>
> HTH,
>
> Peter
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On Wed, Jan 25, 2012 at 1:35 PM, Clem Rock <lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:> Peter - big thanks for your help. You were right - I meant to say > "the layouts table can have many photos" > > Looks like this was the winner for me: > > @properties = Property.paginate(:page => params[:page], :per_page => > 20).includes(:photos).includes(:layouts).order("properties.modify_date, > layouts.modify_date").all >TL;DR : remove the ''.all'' at the end In my example, I terminated with ''.all'' so that you would get a simple Array as the result. Once you have settled on a certain formula for the @properties, it might be better to not longer write the ''.all'' at the end of the chain. Without the .all'' , you will get an ActiveRecord::Relation on which you can continue to chain conditions etc. The real query will then only be done in a later stage of the calculation when the description of the ActiveRecord::Relation is complete. If you ever test this in rails console, it will seem that the query is always done immediately. That is because irb calls .inspect on the last result of the line. One trick to make this work in rails console is to add ; nil at the end: 1.9.3-p0 :030 > p1 = Parent.order("parents.name") ; nil => nil 1.9.3-p0 :031 > p2 = p1.where("NOT parents.name IS NULL") ; nil => nil 1.9.3-p0 :032 > p3 = p2.includes(:child) ; nil => nil 1.9.3-p0 :033 > p3.all Parent Load (0.6ms) SELECT "parents".* FROM "parents" WHERE (NOT parents.name IS NULL) ORDER BY parents.name Child Load (0.4ms) SELECT "children".* FROM "children" WHERE "children"."parent_id" IN (1, 2, 3) => [#<Parent id: 1, name: "dad", created_at: "2012-01-24 10:05:43", updated_at: "2012-01-24 10:05:43">, #<Parent id: 2, name: "dad", created_at: "2012-01-24 10:06:59", updated_at: "2012-01-24 10:06:59">, #<Parent id: 3, name: "mom", created_at: "2012-01-24 10:07:42", updated_at: "2012-01-24 10:07:42">] 1.9.3-p0 :034 > p4 = p3.order("children.created_at") ; nil => nil 1.9.3-p0 :035 > p4.all SQL (0.7ms) SELECT "parents"."id" AS t0_r0, "parents"."name" AS t0_r1, "parents"."created_at" AS t0_r2, "parents"."updated_at" AS t0_r3, "children"."id" AS t1_r0, "children"."name" AS t1_r1, "children"."parent_id" AS t1_r2, "children"."created_at" AS t1_r3, "children"."updated_at" AS t1_r4 FROM "parents" LEFT OUTER JOIN "children" ON "children"."parent_id" = "parents"."id" WHERE (NOT parents.name IS NULL) ORDER BY parents.name, children.created_at => [#<Parent id: 1, name: "dad", created_at: "2012-01-24 10:05:43", updated_at: "2012-01-24 10:05:43">, #<Parent id: 2, name: "dad", created_at: "2012-01-24 10:06:59", updated_at: "2012-01-24 10:06:59">, #<Parent id: 3, name: "mom", created_at: "2012-01-24 10:07:42", updated_at: "2012-01-24 10:07:42">] HTH, Peter -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.