I have a
SELECT * FROM user WHERE id IN(SELECT manage FROM user WHERE id = 1)
You could create a new table
user_manages, which contains two columns:
user_id. Create a new record in the table for each user a manager manages. Then you could develop a join between the two tables.
SELECT user.* FROM user_manages INNER JOIN user ON user.id = user_manages.user_id WHERE user_manages.manager_id = 1