Sequelize - Count related data and separate by column - sql

Question

I have two tables defined "posts" and "comments". I want to get all posts and a number of there total comments, split by the comment type. Currently I can get the count, but cannot separate by comment type
const Sequelize = require('sequelize');
const sequelize = new Sequelize('postgres://username#localhost:5432/test');
const posts = sequelize.define('posts', {
name: Sequelize.STRING,
})
const comments = sequelize.define('comments', {
title: Sequelize.STRING,
type: Sequelize.STRING
})
posts.hasMany(comments);
comments.belongsTo(posts);
const importData = async () => {
// Insert test data
await sequelize.sync({ force: true });
await posts.create({ id: 1, name: 'Hello World' })
await comments.create({ postId: 1, title: 'This is great', type: 'text' })
await comments.create({ postId: 1, title: 'Thanks', type: 'text' })
await comments.create({ postId: 1, title: 'Oh Yeah', type: 'image' })
await comments.create({ postId: 1, title: 'Oh Yeah', type: 'video' })
// Fetch data
const post = await posts.findAll({
where: { id: 1 },
attributes: ['id', 'name', [sequelize.fn('COUNT', 'comments.id'), 'commentCount']],
include: [{ model: comments, attributes: [] }],
group: ['posts.id']
})
console.log(JSON.stringify(post, null, 4))
}
importData();
Output is
[
{
"id": 1,
"name": "Hello World",
"commentCount": "4"
}
]
Desired Output
[
{
"id": 1,
"name": "Hello World",
"commentCount": { "text": 2, "image": 1, "video": 1 }
}
]
Can this be done through Sequelize, or even raw SQL?

Answer 1

Raw SQL something like:
SELECT P.ID, C.Comment_Count, C.Type
FROM POSTS P
LEFT JOIN (SELECT count(*) Comment_Count, PostID, type
FROM Comments
GROUP BY POSTID, type) C
on P.ID = C.PostID
change
PostID to the column name in comments that is the FK to posts
change ID to the PK in posts.