How would I translate this sqlite query into a postgresql query in Ruby on Rails?

Question

I am trying to filter my posts and I grab them using this query.

@posts = Post.all.includes(:course).where("courses.name IN (#{@user.courses.map(&:name).collect { |s| "'#{s}'"  }.join(',') })").references(:course).order("posts.created_at DESC")

I am not familiar with postgresql and know there are some differences. How do I change this to query in postgres?

Have you tried running that query? It might just work.

MarsAtomic
– MarsAtomic

2016-07-28 03:12:03 +00:00
Commented Jul 28, 2016 at 3:12 — MarsAtomic
– MarsAtomic, Commented Jul 28, 2016 at 3:12

Deepak Mahakale · Accepted Answer · 2016-07-28 12:56:46Z

1

Your query will work as it is. But you can modify the query to avoid the unnecessary operations you are doing:

@posts = 
  Post.all.includes(:course).where("courses.name IN (?)", @user.courses.map(&:name)).order("posts.created_at DESC")

Rails will take care of joining the values in this array @user.courses.map(&:name)

You don't need to do it manually.

answered Jul 28, 2016 at 12:56

Deepak Mahakale

23.8k10 gold badges73 silver badges94 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Ryan Over a year ago

You are right, it works, I was switching to postgres as I posted this question, but Im glad you show me this simplified query, thank you!

Collectives™ on Stack Overflow

How would I translate this sqlite query into a postgresql query in Ruby on Rails?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related