subquery from the mysql

Question

여기서 내가 뭘 잘못하고 있니? 모든 조인 된 테이블이 올바른 세트에 조인되도록 내 FROM으로 하위 쿼리를 사용하려고합니다.

SELECT 
    active_users.username as username, 
    active_users.computer_name as computer_name, 
    alert.cnt as alerts 

    FROM 
    (SELECT 
     computer_name, 
     username 
     FROM computers 

     INNER JOIN users 
     on users.computer_id = computers.computer_id 

     WHERE computers.account_id = :cw_account_id AND computers.status = :cw_status 
    ) AS active_users 

    LEFT JOIN 
     (SELECT 
      user_id, 
      count(*) as cnt 
     from logs 
     group by user_id 
    ) AS alert 
     on alert.user_id = active_users.user_id 

Answer 1

당신은 첫 번째 하위 쿼리에 user_id를 선택해야합니다

SELECT active_users.username as username, active_users.computer_name as computer_name, 
     alert.cnt as alerts 
FROM (SELECT user_id, computer_name, username 
     FROM computers INNER JOIN 
      users 
      on users.computer_id = computers.computer_id 
     WHERE computers.account_id = :cw_account_id AND computers.status = :cw_status 
    ) active_users LEFT JOIN 
     (SELECT user_id, count(*) as cnt 
     from logs 
     group by user_id 
    ) alert 
     on alert.user_id = active_users.user_id;