CODEWITHSUNDEEP
mysqlmany-to-many
stackOverFlew
stackOverFlew

Reputation: 1499

Many to many relationship with friends

I have a many to many table which keeps track of friendship.

I need to know that both friends approved each other.

For example, when a person asks to be a friend, their id gets put in self_uuid and the friends in friend_uuid. When the friend approves the request the same thing happens, just the other way around.

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how do find all people that have mutually approved each other? how do i find all the people that have NOT mutually approved each other?

Upvotes: 0

Views: 134

Answers (1)

Barmar
Barmar

Reputation: 780842

Mutual approval:

select f1.self_uuid, f1.friend_uuid
from friends f1
join friends f2 on f1.self_uuid = f2.friend_uuid and f1.friend_uuid = f2.self_uuid

Friend requests that have not been approved:

select f1.self_uuid, f1.friend_uuid
from friends f1
left join friends f2 on f1.self_uuid = f2.friend_uuid and f1.friend_uuid = f2.self_uuid
where f2.self_uuid is null

Upvotes: 3

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