# 1054 - 'where 절'

Question

나는 오류가 날 :) 도와주세요 위치를 모르는 알 수없는 열 'countf'

SELECT a.*,b.*,users.*, 
    (SELECT msg_text FROM message_private p 
    WHERE p.group_id=a.group_id ORDER BY occured_at DESC LIMIT 1) as message, 
    (SELECT COUNT(f.profile_id) as countf from message_view f WHERE f.profile_id = 'sN07X2' AND f.id_group = b.group_id) 
FROM message_group a 
JOIN message_group b ON a.group_id=b.group_id 
INNER JOIN users ON users.profile_id = b.profile_id 
WHERE a.profile_id = 'sN07X2' 
AND b.profile_id != a.profile_id AND countf != 0 ORDER BY a.message_group_id DESC LIMIT 9 

Answer 1

문제는 당신이에서 열 별칭을 참조하려고하는 것입니다 WHERE 절의 SELECT 목록 당신은 결과를 얻기 위하여는 message_view 테이블과 조인을 사용보고 할 수 있습니다, 당신은 별명에 필터링 할 수 있습니다

SELECT a.*,b.*,users.*, 
    (SELECT msg_text 
    FROM message_private p 
    WHERE p.group_id=a.group_id 
    ORDER BY occured_at DESC LIMIT 1) as message, 
    f.countf 
FROM message_group a 
INNER JOIN message_group b ON a.group_id=b.group_id 
INNER JOIN users ON users.profile_id = b.profile_id 
LEFT JOIN 
(
    SELECT COUNT(profile_id) countf, id_group 
    FROM message_view 
    WHERE profile_id = 'sN07X2' 
    GROUP BY id_group 
) f 
    on f.id_group = b.group_id 
WHERE a.profile_id = 'sN07X2' 
    AND b.profile_id != a.profile_id 
    AND countf != 0 
ORDER BY a.message_group_id DESC 
LIMIT 9 

Answer 2

문제는 하위 쿼리 에 countf를 정의하고가 참조하려고한다는 것입니다 그것은 where 절에 있습니다. 대신, 외부 선택의 as countf이 있고 having 절을 사용할 필요가 :

SELECT a.*,b.*,users.*, 
    (SELECT msg_text FROM message_private p 
    WHERE p.group_id=a.group_id ORDER BY occured_at DESC LIMIT 1) as message, 
    (SELECT COUNT(f.profile_id) as countf from message_view f WHERE f.profile_id = 'sN07X2' AND f.id_group = b.group_id 
    ) as countf 
FROM message_group a 
JOIN message_group b ON a.group_id=b.group_id 
INNER JOIN users ON users.profile_id = b.profile_id 
WHERE a.profile_id = 'sN07X2' 
AND b.profile_id != a.profile_id 
having countf <> 0 
ORDER BY a.message_group_id DESC LIMIT 9