Rails：在单个查询中从联接表获取字段

Question

Starting with rails, i want to create a request with dynamic selection and dynamic sorting, like following examples (in SQL):

    select * from books join authors on author_id = books.id 
    where books.title like '%something%'
    order by author.name, books.title

or

    select * from books join authors on author_id = books.id 
    where books.title like '%something%'
    order by books.title, author.name

Author has_many books, book belongs to author.

I code this with two nested loops. In the first case, Author (sorted by name) is read first then Book (sorted by title), in the second case, Book first then author. I can then print together books fields and authors fields. The loops must reflect the hierarchy of sort fields.

But many other fields exist, and dynamic selection/ordering may be any field(s).

Is there a way to write a single 'each' loop, where books fields and authors fields would be available together, like with above sql examples. My problem is to get fields from several tables on one single line.

What would the 'find' request be?

Thanks for your help.

Answer 1

Your basic query would be something like:

@books = Book.where("title LIKE ?", "%{something}%").joins(:author).order("author.name ASC, books.title ASC")

As for controlling the sorting, you can break that into scopes that get conditionally added depending on your params.