Reputation: 59
Need advice, how to write complex query in Ruby.
Query in PHP project:
$get_trustee = db_query("SELECT t.trustee_name,t.secret_key,t.trustee_status,t.created,t.user_id,ui.image from trustees t
left join users u on u.id = t.trustees_id
left join user_info ui on ui.user_id = t.trustees_id
WHERE t.user_id='$user_id' AND trustee_status ='pending'
group by secret_key
ORDER BY t.created DESC")
My guess in Ruby:
get_trustee = Trustee.find_by_sql('SELECT t.trustee_name, t.secret_key, t.trustee_status, t.created, t.user_id, ui.image FROM trustees t
LEFT JOIN users u ON u.id = t.trustees_id
LEFT JOIN user_info ui ON ui.user_id = t.trustees_id
WHERE t.user_id = ? AND
t.trustee_status = ?
GROUP BY secret_key
ORDER BY t.created DESC',
[user_id, 'pending'])
Upvotes: 1
Views: 476
Reputation: 4636
Do you mean Ruby with ActiveRecord? Are you using ActiveRecord and/or Rails? #find_by_sql
is a method that exists within ActiveRecord. Also it seems like the user table isn't really needed in this query, but maybe you left something out? Either way, I'll included it in my examples. This query would work if you haven't set up your relationships right:
users_trustees = Trustee.
select('trustees.*, ui.image').
joins('LEFT OUTER JOIN users u ON u.id = trustees.trustees_id').
joins('LEFT OUTER JOIN user_info ui ON ui.user_id = t.trustees_id').
where(user_id: user_id, trustee_status: 'pending').
order('t.created DESC')
Also, be aware of a few things with this solution:
users_trustees.each { |u| u['image'] }
id
and your timestamps being called created_at
and updated_at
.If you set up your ActiveRecord relationships and classes properly, then this query is much easier:
class Trustee < ActiveRecord::Base
self.primary_key = 'trustees_id' # wouldn't be needed if the column was id
has_one :user
has_one :user_info
end
class User < ActiveRecord::Base
belongs_to :trustee, foreign_key: 'trustees_id' # relationship can also go the other way
end
class UserInfo < ActiveRecord::Base
self.table_name = 'user_info'
belongs_to :trustee
end
Your "query" can now be ActiveRecord goodness if performance isn't paramount. The Ruby convention is readability first, reorganizing code later if stuff starts to scale.
Let's say you want to get a trustee's image:
trustee = Trustee.where(trustees_id: 5).first
if trustee
image = trustee.user_info.image
..
end
Or if you want to get all trustee's images:
Trustee.all.collect { |t| t.user_info.try(:image) } # using a #try in case user_info is nil
It seems like trustee is just a special-case user of some sort. You can use STI if you don't mind restructuring you tables to simplify even further.
This is probably outside of the scope of this question so I'll just link you to the docs on this: http://api.rubyonrails.org/classes/ActiveRecord/Base.html see "Single Table Inheritance". Also see the article that they link to from Martin Fowler (http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html)
http://guides.rubyonrails.org/association_basics.html http://guides.rubyonrails.org/active_record_querying.html
Upvotes: 4
Reputation: 1303
Yes, find_by_sql
will work, you can try this also:
Trustee.connection.execute('...')
or for generic queries:
ActiveRecord::Base.connection.execute('...')
Upvotes: 0