MYSQL Select from tables based on multiple rows

Question

I have a table called user_meta. In that table I have the following columns: ID, userID, meta_key, meta_value

Answer 1

You need to join with user_meta once for each attribute you want to match.

SELECT u.*
FROM users AS u
JOIN user_meta AS m1 ON u.id = m1.userID
JOIN user_meta AS m2 ON u.id = m2.userID
WHERE m1.meta_key = 'companyID' AND m1.meta_value = :companyID
AND m2.meta_key = 'user_type' AND m2.meta_value = 'staff'