按属性或JOIN表中的存在性查询行

Question

I have the entities A and B (with their respective tables). Those entities have a N:M relationship, so there is an AB table.

The A entity has a disabled boolean field.

I want to get all entities from A that ( are not disabled OR are in the AB table and belong to B entity with id 1 ) using ActiveRecord.

Example:

A  
| id | name | disabled |
| a1 | foo  | false    |
| a2 | bar  | false    |
| a3 | zoo  | true     |
| a4 | hoo  | true     |

B
| id | name |
| 1  | Bob  |
| 2  | Jen  |

AB
|Aid | Bid |
| a3 | 1   |

A entities for Bob: foo , bar ans zoo .

Answer 1

A.includes(:bs).where('as.disabled = false OR bs.id = 1')

Answer 2

A.where(:disabled => false ) will find all the entries from A that are not disabled and B.find_by_id(1).as will find all the entries from A that belong to B entity with id 1. A.where(:disabled => false ) | B.find_by_id(1).as A.where(:disabled => false ) | B.find_by_id(1).as taking OR of the 2 arrays gives the required entries.

requeried_entries = A.where(:disabled => false ) | B.find_by_id(1).as