[SQL/코드카타] 유저별 confirmed 의 비율 ( 평균이 바로 비율 )

문제 더보기Table: Signups+----------------+----------+| Column Name | Type |+----------------+----------+| user_id | int || time_stamp | datetime |+----------------+----------+user_id is the column of unique values for this table.Each row contains information about the signup time for the user with ID user_id. Table: Confirmations+----------------+----------+| Column Name | ..