Ruby on rails distinct

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Webbadd_index :campaigns, [:appeal_id, :user_id], unique: true in my migration. Then run the command. rails db:create db:migrate which actually created my database again and … Webb31 aug. 2008 · As I mentioned here, in Rails 4, using (...).uniq.count(:user_id) as mentioned in other answers (for this question and elsewhere on SO) will actually lead to an extra DISTINCT being in the query: SELECT DISTINCT COUNT(DISTINCT user_id) FROM ... What we actually have to do is use a SQL string ourselves: (...).count("DISTINCT user_id") …

ruby on rails - Pluck unique values from an ActiveRecord …

Webbincludes(*args) public. Specify relationships to be included in the result set. For example: users = User. includes (:address) users.each do user user.address.city end. allows you to access the address attribute of the User model without firing an additional query. This will often result in a performance improvement over a simple join. Webb@no是unique_id的數組。 @grid = Grid.all. @grid is an activeRecord, I want to sort this active record based on the order of @no which is nothing but the unique_id in @grid. 我正在嘗試這個. @grid.sort_by{ h @no.index(h.unique_id) } 它說，它不起作用， ArgumentError：NilClass與14的比較失敗. 我知道正在進行一些 ... hotels in stockton ca near airport

Ruby on Rails Tutorial => .distinct (or .uniq)

Webb31 dec. 2024 · You would have to look up the genre table to get the 'Action' string returned. If you have to make a link from the movie to genre table, that will go something like this: movies = Movie.includes (:genre) movies.first.genre.name # this will return the action string # or, pick a specific movie and look up its genre movies.where (:title => 'xyz ... Webb28 dec. 2016 · I would like to make a column unique in Ruby on Rails migration script. What is the best way to do it? Also is there a way to index a column in a table? I would … lilly\\u0027s soft serve stratford

ruby on rails - Combining distinct with another condition - Stack …

activerecord - Rails: uniq vs. distinct - Stack Overflow

Webb15 mars 2024 · ActiveRecord Rails: Get records where a field is unique/distinct. I have a project Ruby 2.4.0 and Rails 5.0.1 and a model with the following: class Hospital < … Webbdistinct (ActiveRecord::QueryMethods) - APIdock Welcome Register Projects Help About Blog Use OpenIDLoginPasswordOpenID URLRemember me RSpec Ruby Ruby on Rails … hotels in stokesley north yorkshireWebb31 jan. 2016 · If using the artist's songs association, you can select distinct on genre, then map over the results to just return the strings: artist.songs.select('distinct … lilly\\u0027s soul food

"Webb17 feb. 2024 · About. Software Engineer who enjoys solving problems efficiently and creatively. My technical skills include React, Ruby on Rails, Javascript, HTML, CSS, and Stimulus. In additional to technical ... " - Ruby on rails distinct

Ruby on rails distinct

ruby on rails - SearchKick x vs × - Stack Overflow

Webb31 jan. 2016 · 3. I have the following association: Artist has_many Songs. Hence, I can get an artist's songs by doing: artist.songs. However, I would like to get only the songs' genre: artist.songs.pluck (:genre) But, this genre may appear multiple times in the results; I would only like to get unique genre values. Unfortunately, pluck isn't of any help here ... WebbRuby on Rails ActiveRecord Query Interface .distinct (or .uniq) Fastest Entity Framework Extensions Bulk Insert Bulk Delete Bulk Update Bulk Merge Example # If you want to …

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Webb9 okt. 2024 · The Polymorphic association is a Ruby on Rails feature that gives us the freedom to structure model relationships based on real life. This means building cleaner more semantic databases. In a… WebbRails has_many :through. Я пытаюсь создать приложение точки продаж в rails Щас у меня есть модель items. Модель items содержит каждый из разных предметов, переносимых магазином. Теперь я хочу создать модель Orders.

WebbI've done this on a site where people pay to download certain files, and the files are stored in RAILS_ROOT/private.The first thing to know is that you want the web server to handle sending the file, otherwise your app will be held up transmitting large files and this will quickly bring your site to a halt if you have any kind of download volume. Webb28 apr. 2024 · Ruby on Rails distinct query returns array of unique values in specified field. returns array of unique values in name field. Looking out for an equivalent aggregate …

Webb29 sep. 2014 · uniq is a method of Array, so it returns the whole bunch of 120k users and iterates through them one by one using ruby to check the condition. This is definetely the wrong way to do filtering. On the other hand, DISTINCT(users.id) is SQL condition which is handled by your PostgreSQL server. This one should be executed pretty fast. In case it … WebbRuby on Rails, disebut juga Rails, adalah sebuah kerangka kerja aplikasi web sumber terbuka yang berjalan via bahasa pemrograman Ruby. Ia merupakan kerangka kerja full-stack : memampukan pembuatan laman dan aplikasi yang mengumpulkan informasi dari server web, berkomunikasi dengan atau memanggil sebuah kueri dari server web, dan …

Webb7 aug. 2015 · In Rails 4, has_many :products, :through => :orders, :uniq => true is deprecated. Instead, you should now write has_many :products, -> { distinct }, through: …

Webb之所以發生競爭，是因為Rails無法鎖定數據庫，並且經常同時運行多個線程。要了解競爭條件是如何發生的，請考慮進行唯一性檢查所需的條件，然后給出兩個線程的示例：假設人員A和B要保存一個新的BlogPost，其屬性name必須唯一。人物A按下保存按鈕 lilly\\u0027s spaWebb10 apr. 2024 · I have a few questions related to SearchKick, but they seem closely related so I'm going to ask both: How can I distinct between × (times) and x? The proper version in the database is times, but p... hotels in stoney creek hamilton ontarioWebb> User.joins(:donations).order('donations.created_at').uniq.count (3.2ms) SELECT DISTINCT COUNT(DISTINCT "users"."id") FROM "users" INNER JOIN "donations" ON … hotels in stone mountain georgia parkWebb30 juli 2015 · Here is a raw MySQL query which will give you the result set you want: SELECT lang1.*. FROM Languages lang1 INNER JOIN ( SELECT l.Locale, MAX (l.Version) AS MaxVersion FROM Languages l GROUP BY l.Locale ) lang2 ON lang1.Locale = lang2.Locale AND lang1.Version = lang2.MaxVersion. hotels in stone mountain ga 30083Webb6 okt. 2024 · How can I order by .select().distinct() ? Controller method: @line_items_sold = LineItem.where() @vendor_line_items = @line_items_sold.select(:store_title).distinct ... hotels in stone mountain ga 30087Webb127. All the above answers are missing how to validate the uniqueness of multiple attributes in a model. The code below intends to tell how to use multiple attributes in a scope. validates :country, uniqueness: { scope: [:medium, :another_medium] } It validates uniqueness of country in all rows with values of medium and another_medium. lilly\u0027s soul foodWebb15 juli 2024 · It’s quite easy to set database unique index (es) for any column or set of columns in rails. However, some database constraint in rails can be tricky. A quick look at setting a unique index for one or more column This is quite as simple as running a … lilly\u0027s soul food menu