Feature Request - RIGHT JOIN

Given that we currently cannot limit the associated records (#1897), I’ve been exploring other options; one of the ideas is to select the associated records and right-join onto a particular main record in order to retrieve both the main and associated records.

Consider the case where there is a post, and that post may or may not have comments, and no more than 5 latest comments are to be retrieved:

// Ideally, we'd just do this in order to get 1 post with 0-5 latest comments:
Post.findOne({
  where: { id: 123 },
  include: [{
    model: Comment,
    required: false,
    order: [ ['timestamp'], 'DESC'] ]
    limit: 5
  }]
});

One of the workarounds I’m exploring is to select the comments of a post and include the post:

// This only retrieves latest 1-5 comments for the post along with the post.
// If the post has no comments, result set would be empty, obviously.
Comment.findOne({
  where: { post_id: 123 },
  include: [{
    model: Post,
    required: false
  }],
  order: [ ['timestamp', 'DESC'] ],
  limit: 5
});

A similar RIGHT JOIN would be able to retrieve 0-5 latest comments along with the post regardless there are comments or not:

SELECT c.*, p.*
FROM Comments AS c
RIGHT JOIN Posts AS p ON c.post_id = p.id
WHERE p.id = 123

// Perhaps something like:
Comment.findOne({
  //where: { post_id: 123 }, // Not sure if this still makes sense.
  include: [{
    model: Post,
    where: { id: 123 },
    required: false
  }],
  order: [ ['timestamp', 'DESC'] ],
  limit: 5
});

@janmeier @mickhansen Is this something that could be implemented for the time being while #1897 is being worked on? Thanks.

[TakanashiOuken]

This was 4 years ago. But we still don’t have RIGHT OUTER JOIN for Sequelize ?

[marc-ferrer]

That’s why i did not reference any of you in my comment. I just could not find a better place to ask this, than an issue called “Feature Request - RIGHT JOIN”

I appreciate your help, I guess I could use raw queries as you suggest and populate the models manually.