what I'm trying to do is to write something like the next query:
SELECT *
FROM Customers c
LEFT JOIN CustomerAccounts ca
ON ca.CustomerID = c.CustomerID
AND c.State = 'NY'
Notice that I'm not using any WHERE clause, but I need to my JOIN have a condition. I cannot make it work in Ruby on Rails.
Can you help me out?
You can join the tables with LEFT JOIN. Just pass the join condition in joins and you will get the expected result
Customer.joins("LEFT JOIN CustomerAccounts
ON CustomerAccounts.CustomerID = Customers.CustomerID
AND Customers.State = 'NY'")
#=> SELECT * FROM Customers LEFT JOIN CustomerAccounts ON CustomerAccounts.CustomerID = Customers.CustomerID AND Customers.State = 'NY'
Note: just .joins() does INNER JOIN so you need to specify the join with condition
Your SQL code, translated to activerecord, would look as follows (using joins):
Customer.where(state: 'NY').joins(:customer_accounts)
The code assumes, you have the association set up:
class Customer
has_many :customer_accounts
end
Related
How do you query on Ruby on Rails or translate this query on Ruby on Rails?
SELECT
orders.item_total,
orders.total,
payments.created_at,
payments.updated_at
FROM
public.payments,
public.orders,
public.line_items,
public.variants
WHERE
payments.order_id = orders.id AND
orders.id = line_items.order_id AND
This is working on Postgres but I'm new to RoR and it's giving me difficulty on querying this sample.
So far this is what I have.
Order.joins(:payments,:line_items,:variants).where(payments:{order_id: [Order.ids]}, orders:{id:LineItem.orders_id}).distinct.pluck(:email, :id, "payments.created_at", "payments.updated_at")
I have a lot of reference before asking a question here are the links.
How to combine two conditions in a where clause?
Rails PG::UndefinedTable: ERROR: missing FROM-clause entry for table
Rails ActiveRecord: Pluck from multiple tables with same column name
ActiveRecord find and only return selected columns
https://guides.rubyonrails.org/v5.2/active_record_querying.html
from all that link I produced this code that works for testing.
Spree::Order.joins(:payments,:line_items,:variants).where(id: [Spree::Payment.ids]).distinct.pluck(:email, :id)
but when I try to have multiple queries and pluck a specific column name from a different table it gives me an error.
Update
So I'm using Ransack to query I produced this code.
#search = Spree::Order.ransack(
orders_gt: params[:q][:created_at_gt],
orders_lt: params[:q][:created_at_lt],
payments_order_id_in: [Spree::Order.ids],
payments_state_eq: 'completed',
orders_id_in: [Spree::LineItem.all.pluck(:order_id)],
variants_id_in: [Spree::LineItem.ids]
)
#payment_report = #search.result
.includes(:payments, :line_items, :variants)
.joins(:line_items, :payments, :variants).select('payments.response_code, orders.number, payments.number')
I don't have error when I remove the select part and I need to get that specific column. Is there a way?
You just have to make a join between the tables and then select the columns you want
Spree::Order.joins(:payments, :line_items).pluck("spree_orders.total, spree_orders.item_total, spree_payments.created_at, spree_payments.updated_at")
or
Spree::Order.joins(:payments, :line_items).select("spree_orders.total, spree_orders.item_total, spree_payments.created_at, spree_payments.updated_at")
That is equivalent to this query
SELECT spree_orders.total,
spree_orders.item_total,
spree_payments.created_at,
spree_payments.updated_at
FROM "spree_orders"
LEFT OUTER JOIN "spree_payments" ON "spree_payments"."order_id" = "spree_orders"."id"
LEFT OUTER JOIN "spree_line_items" ON "spree_line_items"."order_id" = "spree_orders"."id"
You can use select_all method.This method will return an instance of ActiveRecord::Result class and calling to_hash on this object would return you an array of hashes where each hash indicates a record.
Order.connection.select_all("SELECT
orders.item_total,
orders.total,
payments.created_at,
payments.updated_at
FROM
public.payments,
public.orders,
public.line_items,
public.variants
WHERE
payments.order_id = orders.id AND
orders.id = line_items.order_id").to_hash
I'm trying to use SQL to get information from a Postgres database using Rails.
This is what I've tried:
Select starts_at, ends_at, hours, employee.maxname, workorder.wonum from events where starts_at>'2018-03-14'
inner join employees on events.employee_id = employees.id
inner join workorders on events.workorder_id = workorders.id;
I get the following error:
ERROR: syntax error at or near "inner"
LINE 2: inner join employees on events.employee_id = employees.id
Sami's comment is correct, but since this question is tagged with ruby-on-rails you can try to use ActiveRecord's API to do the same:
Make sure that your models relations are defined
class Event < ActiveRecord::Base
belongs_to :employee
belongs_to :workorder
end
And then you can do something like:
Event
.where('starts_at > ?', '2018-03-14')
.joins(:employee, :workorder)
or
Event
.joins(:employee, :workorder)
.where('starts_at > ?', '2018-03-14')
And you don't need to worry which one goes first.
In general, it's suboptimal to create the SQL queries in rails if you don't absolutely need to because they're harder to maintain.
You request should look at this :
select starts_at, ends_at, hours, employee.maxname, workorder.wonum
from events
inner join employees on events.employee_id = employees.id
inner join workorders on events.workorder_id = workorders.id
where starts_at>'2018-03-14';
I have two associations like surgical_diseases and eye_disease.I want to get the Ored result of the two active relation.But the below code gave me an array.
has_many :surgical_diseases
has_many :eye_disease
scope :all_disease ->(name) { joins(:surgical_diseases).where('surgical_diseases.name IN (?)') | joins(:eye_disease).where('eye_disease.name IN (?)') }
I have seen active-record-union gem but that would only work with active-record 4.I am currently using rails 3.2 so not able to use that.
I also saw that this functionality will come with rails5 with dhh's commit.But not sure how will I fix this with rail3 now.
I tried my best to make understanding of my question.Please let me know if anything else information is require.
Thanks in advance!
You would probably need to get the ids using find_by_sql and then find those ids to get ActiveRecord::Relation.
scope :all_disease ->(name) {
ids = YourTable.find_by_sql <<-SQL
SELECT your_table.id FROM your_table INNER JOIN surgical_diseases sd ON sd.your_table_id=your_table.id WHERE sd.name IN (#{name})
UNION
SELECT your_table.id FROM your_table INNER JOIN eye_diseases ed ON ed.your_table_id=your_table.id WHERE ed.name IN (#{name})
SQL
YourTable.where(id: ids)
}
Perhaps, left outer join can help you:
scope :all_disease ->(name) {
joins('LEFT OUTER JOIN surgical_diseases ON surgical_diseases.whatever_table_for_your_models_id = whatever_table_for_your_models.id')
.joins('LEFT OUTER JOIN eye_diseases ON eye_diseases.whatever_table_for_your_models_id = .whatever_table_for_your_models.id')
.where('surgical_diseases.name IN (?) OR eye_diseases.name IN (?)', name)
I'm trying to understand why I don't receive any records on a ruby on rails app using postgresql. This is the SQL query that is being executed:
SELECT g.program_id, g.title,
COALESCE(COUNT(pr), 0) AS ac, g.default
FROM groups AS g
LEFT OUTER JOIN memberships AS m ON m.group_id = g.id
LEFT OUTER JOIN progresses AS pr ON m.id = pr.participant_id
AND (pr.status = 'completed')
WHERE g.program_id = ANY(#1)
GROUP BY g.id
ORDER BY g.program_id, g.position, g.id
My question is: what does the ANY(#1) means?
Please have pacience, as I'm a ruby/rails/postgresql newbie.
Thanks!
Update: added some aditional code. Plese don't ident the query below as it is already idented above.
class StatsComponents::CompletedActivitiesPerGroupStats
include StatsComponent::Interface
GROUP_ACTIVITIES = <<-SQL
g.program_id, g.title, COALESCE(COUNT(pr), 0) AS ac, g.default
FROM groups AS g
LEFT OUTER JOIN memberships AS m ON m.group_id = g.id
LEFT OUTER JOIN progresses AS pr ON m.id = pr.participant_id
AND (pr.status = 'completed')
WHERE g.program_id = ANY(#1)
GROUP BY g.id
ORDER BY g.program_id, g.position, g.id
SQL
def generate
...
It selects records where g.program_id has a value existing in the array returned by #1 request, which they set as a query parameter (for example SELECT...) somewhere further in the program.
You can equally use SOME(#1) here.
By the way strictly speaking, this isn't a sql query. While there is no sql.execute or something like that, it's just a multiline string assignment.
Let's say that I have 4 models which are related in the following ways:
Schedule has foreign key to Project
Schedule has foreign key to User
Project has foreign key to Client
In my Schedule#index view I want the most optimized SQL so that I can display links to the Schedule's associated Project, Client, and User. So, I should not pull all of the columns for the Project, Client, and User; only their IDs and Name.
If I were to manually write the SQL it might look like this:
select
s.id,
s.schedule_name,
s.schedule_type,
s.project_id,
p.name project_name,
p.client_id client_id,
c.name client_name,
s.user_id,
u.login user_login,
s.created_at,
s.updated_at,
s.data_count
from
Users u inner join
Clients c inner join
Schedules s inner join
Projects p
on p.id = s.project_id
on c.id = p.client_id
on u.id = s.user_id
order by
s.created_at desc
My question is: What would the ActiveRecord code look like to get Rails 3 to generate that SQL? For example, somthing like:
#schedules = Schedule. # ?
I already have the associations setup in the models (i.e. has_many / belongs_to).
I think this will build (or at least help) you get what you're looking for:
Schedule.select("schedules.id, schedules.schedule_name, projects.name as project_name").joins(:user, :project=>:client).order("schedules.created_at DESC")
should yield:
SELECT schedules.id, schedules.schedule_name, projects.name as project_name FROM `schedules` INNER JOIN `users` ON `users`.`id` = `schedules`.`user_id` INNER JOIN `projects` ON `projects`.`id` = `schedules`.`project_id` INNER JOIN `clients` ON `clients`.`id` = `projects`.`client_id`
The main problem I see in your approach is that you're looking for schedule objects but basing your initial "FROM" clause on "User" and your associations given are also on Schedule, so I built this solution based on the plain assumption that you want schedules!
I also didn't include all of your selects to save some typing, but you get the idea. You will simply have to add each one qualified with its full table name.