How to find to the people have liked me?

Development
11

This query might be close to what you want, tweak to suit eg. add a WHERE user_id = an id for a single user

SELECT 
 user_actions.user_id 
 , array_agg(DISTINCT user_actions.acting_user_id) 
FROM user_actions 
WHERE 
 user_actions.action_type = 2 
GROUP BY user_actions.user_id

“2” is “liked” and “acting_user_id” is the “giver”

You may prefer to use AR pluck, but it would be the same table