在两个模型上匹配has_many关联

Question

I have a job which has_many categories I have a business which has_many categories.

Currently I'm only assigning 1 category to both job and a business but this will change later which is why I've created the has_many association.

The categories assigned to businesses and jobs are from the same category table selected with a select menu with the intention of matching them.

If have a job, how can I find businesses that match the jobs category.

For example job = Job.find(1)

> job.categories.first.name
 => "programmer"

If I want to find all Businesses listed that have the programmer category how can I do this?

I think I might need a join or include similar to this but I'm not sure how this should be written exactly.

Business.includes(:categories).where(:categories == ...)

Answer 1

Your code is almost right. This should work:

Business.joins(:categories).where(categories: {name: 'programmer'})

Or if you have multiple categories:

Business.joins(:categories).where(categories: {name: ['programmer', 'other']})