1934. Confirmation Rate.sql

# Write your MySQL query statement below
SELECT 
    s.user_id,
    ROUND(AVG(CASE 
              WHEN c.action = 'confirmed' THEN 1
              ELSE 0
              END),2) AS confirmation_rate
FROM 
    Signups s
LEFT JOIN 
    Confirmations c 
    ON s.user_id = c.user_id
GROUP BY 
    s.user_id