ruby on rails - Activerecord complex join -

i have problem activerecord join.

i have object "user" follows items, , object "content" has followable items (brands in case) associated.

u , c user , content.

now have these 2 queries:

bf = u.follows.where('followable_type = ?', "brand").map(&:followable_id)  [22, 188, 182, 71, 24, 2]  c.brands.map(&:id)  [2]

i need obtain array values present in both query, in case [2].

how can write single query?

something like

bf = u.follows.where('followable_type = ?', "brand").where followable_id inside c.brands_ids

update:

brands = author.follows.where('followable_type = ?', "brand").where(followable_id: content.brands.map(&:id)).map(&:followable).map(&:name).join(', ')

try using query:

sql_subquery = u.follows.where(followable_type: 'brand').select(:followable_id).to_sql u.follows.where( followable_id: sql_subquery )

also, advice, try using complete names variables. makes code more readable, you.

Brazzel