I need some fresh eye to my object query. The idea is to show from db all users which have only one client (belongs_to :user), which are not subscribed.
models
user
has_many :customers
has_many :customers_users
customer
has_many :customers_users
belongs_to :user
customers_user
belongs_to :user
belongs_to :customer
customer_subscription
belongs_to :customer
query
Customer.
joins("LEFT JOIN customer_subscriptions ON customer_subscriptions.customer_id = customers.id").
where(customer_subscriptions: { id: nil }).
joins("RIGHT JOIN customers_users ON customers_users.customer_id = customers.id").
group(:user_id).
having("count(user_id) = ?", 1).
count
But after all I've got only user_id without data such as name, email, nickname etc. I thought the problem is with count at the end but without count I received an error NoMethodError: undefined method 'having' for main:Object
Is it possible to reach these data in one query?
In your case I guess a negative condition in the join would work. So the query would be like:
SELECT * FROM users
INNER JOIN customers
ON customers.user_id = users.id
INNER JOIN customers_subscriptions
ON customers_subscriptions.customer_id != customers.user_id
GROUP BY users.id
HAVING COUNT(users.id) = 1
So having:
Users:
+----+-------+------------+----------------------------+----------------------------+
| id | email | name | created_at | updated_at |
+----+-------+------------+----------------------------+----------------------------+
| 1 | NULL | seb | 2019-04-27 19:16:09.043251 | 2019-04-27 19:16:09.043251 |
| 2 | NULL | sab | 2019-04-27 19:16:09.150315 | 2019-04-27 19:16:09.150315 |
| 3 | NULL | washington | 2019-04-27 19:58:01.737446 | 2019-04-27 19:58:01.737446 |
+----+-------+------------+----------------------------+----------------------------+
Customers:
+----+------------+-------+---------+----------------------------+----------------------------+
| id | name | email | user_id | created_at | updated_at |
+----+------------+-------+---------+----------------------------+----------------------------+
| 1 | Sab | NULL | 1 | 2019-04-27 19:16:09.254955 | 2019-04-27 20:02:47.636143 |
| 2 | Seb | NULL | 2 | 2019-04-27 19:16:09.313268 | 2019-04-27 20:02:55.741603 |
| 3 | Washington | NULL | 3 | 2019-04-27 19:58:22.711897 | 2019-04-27 19:58:45.213720 |
| 4 | Eminem | NULL | 3 | 2019-04-27 19:58:52.820731 | 2019-04-27 20:03:02.465681 |
+----+------------+-------+---------+----------------------------+----------------------------+
Customers Subscriptions:
+----+-------------+----------------------------+----------------------------+
| id | customer_id | created_at | updated_at |
+----+-------------+----------------------------+----------------------------+
| 1 | 1 | 2019-04-27 19:16:10.041788 | 2019-04-27 19:16:10.041788 |
| 2 | 3 | 2019-04-27 20:04:16.464446 | 2019-04-27 20:04:16.464446 |
+----+-------------+----------------------------+----------------------------+
The result should be:
+----+-------+------+----------------------------+----------------------------+----+------+-------+---------+----------------------------+----------------------------+----+-------------+----------------------------+----------------------------+
| id | email | name | created_at | updated_at | id | name | email | user_id | created_at | updated_at | id | customer_id | created_at | updated_at |
+----+-------+------+----------------------------+----------------------------+----+------+-------+---------+----------------------------+----------------------------+----+-------------+----------------------------+----------------------------+
| 1 | NULL | seb | 2019-04-27 19:16:09.043251 | 2019-04-27 19:16:09.043251 | 1 | Sab | NULL | 1 | 2019-04-27 19:16:09.254955 | 2019-04-27 20:02:47.636143 | 2 | 3 | 2019-04-27 20:04:16.464446 | 2019-04-27 20:04:16.464446 |
+----+-------+------+----------------------------+----------------------------+----+------+-------+---------+----------------------------+----------------------------+----+-------------+----------------------------+----------------------------+
So an AR code for that could be:
User.
joins(:customers).
joins('INNER JOIN customers_subscriptions ON customers_subscriptions.customer_id != customers.user_id').
group(:id).
having('COUNT(users.id) = 1')
I have this chain of models:
And I have a list of suboptions. I would like to group_by the suboptions by each of the above fathers.
So, it would be divided into Categories, which would be divided into activities, which would be divided into options. Do you see?
How can I do this??
Suboptions.all.group_by(???)
# or
Suboptions.all.order_by(????)
# or ????
Example:
Suboptions
+----+-----------+
| id | option_id |
+----+-----------+
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 4 |
| 5 | 3 |
+----+-----------+
Options
+----+-------------+
| id | activity_id |
+----+-------------+
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 3 |
+----+-------------+
Activities
+----+-------------+
| id | category_id |
+----+-------------+
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
+----+-------------+
Categories
+----+------+
| id | name |
+----+------+
| 1 | cat1 |
| 2 | cat2 |
+----+------+
then the search should return the suboptions with ids in the following order: [1,5,4,2,3]
( try to visualize it from the category to the suboption )
Depending on the size of the data set, sounds like you want to do a join, followed by an order
Suboption.joins(option: {activity: :category}).order('categories.name')
Will that work for you?
I populate book items into my Book model,
But I found there are many items have the same id.
So, how to create unique id for items. To prevent many items from having the same id ?
Here is the book model code
# encoding: utf-8
class Book < ActiveRecord::Base
attr_accessible :name, :isbn ,:price ,:comment ,:author ,:sale_type ,:publisher ,:sn ,:category
attr_accessible :location, :category, :release_date
validates_uniqueness_of :sn
Here are the part of my items
irb(main):058:0> Book.all[1..10]
+-----+------+-----+-----+------+------+-----+------+-----+-----+------+------+-----+------+
| id | pric | com | cre | upda | rele | loc | sn | isb | aut | sale | name | cat | publ |
+-----+------+-----+-----+------+------+-----+------+-----+-----+------+------+-----+------+
| 118 | 4543 | 作 | 201 | 2013 | 2006 | --- | 2124 | 978 | 趙 | prom | 求索 | 商 | 聯經 |
| 118 | 872 | 馬 | 201 | 2013 | 2013 | --- | 2124 | 978 | 黎 | prom | 告別 | 政 | 聯經 |
| 118 | 2105 | 某 | 201 | 2013 | 2012 | --- | 2124 | 978 | 吳 | prom | 複眼 | 政 | 夏日 |
| 118 | 301 | 作 | 201 | 2013 | 2006 | --- | 2124 | 978 | 王 | norm | 天香 | 歷 | 麥田 |
| 118 | 411 | 少 | 201 | 2013 | 2008 | --- | 2124 | 978 | 韓 | norm | 鞋癖 | 商 | 聯經 |
| 119 | 3751 | 有 | 201 | 2013 | 2010 | --- | 2124 | 978 | 紀 | prom | 私家 | 體 | 印刻 |
| 119 | 3361 | 文 | 201 | 2013 | 2010 | --- | 2124 | 978 | 林 | fix_ | 我不 | 體 | 印刻 |
| 119 | 1140 | 何 | 201 | 2013 | 2012 | --- | 2124 | 978 | 邁 | norm | 正義 | 體 | 雅言 |
| 119 | 888 | 一 | 201 | 2013 | 2007 | --- | 2124 | 978 | 福 | fix_ | 生命 | 商 | 究竟 |
| 119 | 3283 | 近 | 201 | 2013 | 2011 | --- | 2124 | 978 | 芮 | norm | 海拉 | 政 | 遠流 |
+-----+------+-----+-----+------+------+-----+------+-----+-----+------+------+-----+------+
here the rake code to generate my data
16 bk = Book.new(:sn => real_sn,:name => book_name, :isbn=>isbn,
17 :price =>Random.rand(200..5000), :location=>location, :category=>["商業","歷史","體育","政治"].sample,
18 :author => author, :sale_type => [:fix_priced, :normal, :promotion].sample, :publisher => publisher,
19 :release_date => rand(10.years).ago, :comment => comment
20 )
Columns in the table I use the Postgre DB
Column | Type | Modifiers
--------------+-----------------------------+----------------------------------------------------
id | integer | not null default nextval('books_id_seq'::regclass)
price | integer |
comment | text |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
release_date | text |
location | text |
sn | bigint |
isbn | bigint |
author | text |
sale_type | text |
name | text |
category | text |
publisher | text |
Indexes:
"books_pkey" PRIMARY KEY, btree (id)
The code above, does not save any record in the database, it just instantiate objects of Book model. You should either save the object after initialization bk.save or use the create method instead of new.
bk = Book.new(:sn => real_sn,:name => book_name, :isbn=>isbn,
:price =>Random.rand(200..5000), :location=>location,
:category=>["商業","歷史","體育","政治"].sample, :author => author,
:sale_type => [:fix_priced, :normal, :promotion].sample,
:publisher => publisher, :release_date => rand(10.years).ago,
:comment => comment)
bk.save
Or alternatively you can use the create method
bk = Book.create(:sn => real_sn,:name => book_name, :isbn=>isbn,
:price =>Random.rand(200..5000), :location=>location,
:category=>["商業","歷史","體育","政治"].sample, :author => author,
:sale_type => [:fix_priced, :normal, :promotion].sample,
:publisher => publisher, :release_date => rand(10.years).ago,
:comment => comment)
Once saved in the database, it will automatically gain a unique id.
I'm using rails 3 and I can't seem to check if a given instance is in a scope, see here:
p = Post.find 6
+----+----------+-------------------------+-------------------------+-------------------------+-----------+
| id | title | publish_date | created_at | updated_at | published |
+----+----------+-------------------------+-------------------------+-------------------------+-----------+
| 6 | asfdfdsa | 2010-03-28 22:33:00 UTC | 2010-03-28 22:33:46 UTC | 2010-03-28 22:33:46 UTC | true |
+----+----------+-------------------------+-------------------------+-------------------------+-----------+
I have a menu scope which looks like:
scope :menu, where("published != ?", false).limit(4)
When I run it I get:
Post.menu.all
+----+------------------+------------------+------------------+-------------------+-----------+
| id | title | publish_date | created_at | updated_at | published |
+----+------------------+------------------+------------------+-------------------+-----------+
| 1 | Lorem ipsum | 2010-03-23 07... | 2010-03-23 07... | 2010-03-28 21:... | true |
| 2 | fdasf | 2010-03-28 21... | 2010-03-28 21... | 2010-03-28 21:... | true |
| 3 | Ruby’s Imple... | 2010-03-28 21... | 2010-03-28 21... | 2010-03-28 21:... | true |
| 4 | dsaD | 2010-03-28 22... | 2010-03-28 22... | 2010-03-28 22:... | true |
+----+------------------+------------------+------------------+-------------------+-----------+
Which is correct, but if I try to check if p is in the the menu scope using: Post.menu.exists?(p) I get true when it should be false
What is the proper way to find out if a given instance of something is in a scope?
Actually, I was able to solve it using that Array method of include? instead of exists?
I have complex form similar to a recent Ryan Bates screencast
The nested elements work fine however. I'm creating or updating a grid of data such as this through a form where the day's prices are the input. My problem begins when they leave one blank. I have the nested_attributes_for option for not saving nils and it works, if they only save one value in a particular row, it saves the correct day however when reloaded, it will place it in the wrong column. I'm not sure how to order the values in a row to the form. IE A saved value for wednesday will appear in the monday column (of the correct row). This doesn't happen if they save all value for a row (then it works perfectly).
Data is stored in the DB like so
ID OBJECT_ID DAYOFWEEK PRICE and displaying like below
+------+----------------+-------+-------+-------+------+-------+
| id | name | Mon | Tue | Wed | Thu | Fri | -> +2 more days etc
+------+----------------+-------+-------+-------+------+-------+
| 1234 | Some name | 87.20 | 87.20 | 87.20 | 82.55| 85.48 |
+------+----------------+-------+-------+-------+------+-------+
| 1234 | Some name | 87.20 | 87.20 | 87.20 | 82.55| 85.48 |
+------+----------------+-------+-------+-------+------+-------+
| 1234 | Some name | 87.20 | 87.20 | 87.20 | 82.55| 85.48 |
+------+----------------+-------+-------+-------+------+-------+
The controller code either building or display these values is like so:
controller
#rooms.each do |r|
((r.room_rates.size+1)..7).each {
r.room_rates.build
}
end
rooms.html.erb
<% #dow = 0 %>
<tr class="room">
<td><%= f.text_field :name %></td>
<% f.fields_for :room_rates do |rates| %>
<%= render 'rates', :f => rates %>
<% #dow += 1 %>
<% end %>
<td class="delete_mode" style="display:none;">
<%= f.hidden_field :_destroy %>
<%= link_to_function "remove", "remove_room(this)" %>
</td>
</tr>
rates.html.erb
<td>
<%= f.text_field :price, :size => 3 %>
<%= f.hidden_field :dayofweek, :value => #dow %>
<%= f.hidden_field :source, :value => 0 %>
</td>
room_rates model (where the data from the form is going)
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
| id | room_id | dayofweek | price | source | created_at | updated_at |
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
| 92745 | 8 | 0 | 1.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92746 | 8 | 1 | 2.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92747 | 8 | 2 | 3.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92748 | 8 | 3 | 4.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92749 | 8 | 4 | 5.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92750 | 8 | 5 | 6.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92751 | 8 | 6 | 7.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92752 | 9 | 3 | 5.0 | 0 | 2010-02-23 14:33:33 +0100 | 2010-02-23 14:33:33 +0100 |
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
ordering in the console
+---------+-----------+-------+--------+---------------------------+---------------------------+
| room_id | dayofweek | price | source | created_at | updated_at |
+---------+-----------+-------+--------+---------------------------+---------------------------+
| 2517 | 0 | | | | |
| 2517 | 1 | | | | |
| 2517 | 2 | 3.0 | 0 | 2010-02-23 17:54:28 +0100 | 2010-02-23 17:54:28 +0100 |
| 2517 | 3 | 4.0 | 0 | 2010-02-23 17:54:28 +0100 | 2010-02-23 17:54:28 +0100 |
| 2517 | 4 | | | | |
| 2517 | 5 | | | | |
| 2517 | 6 | | | | |
+---------+-----------+-------+--------+---------------------------+---------------------------+
The error is when you create the form - because you are depending on the order of the room_rates to be correct, you need to put the empty (built) rates into the correct positions. If each room has many room rates, you need to generate the form so that the rates are at the right day in the week. This code will build that in a new array, and set the new array correctly:
#rooms.each do |r|
new_rates = []
(0..6).each { |dow|
rate = r.room_rates.find_by_dayofweek(dow)
if rate
new_rates << rate
else
new_rates << r.room_rates.build(:dayofweek => dow)
end
}
r.room_rates = new_rates
end
Alternatively, you may be able to just build the missing weeks, if you specify an order for your association:
// In room model
has_many :rates, :order => "dayofweek"
// In controller
#rooms.each do |r|
(0..6).each { |dow|
if not r.room_rates.find_by_dayofweek(dow)
r.room_rates.build(:dayofweek => dow)
end
}
end