-4

我不知道错误在哪里，请帮助我:)

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
4

2 回答 2

0

问题是您试图从 WHERE 子句中的 SELECT 列表中引用列别名。您可能希望查看对message_view表使用 JOIN 以获得结果，然后您可以过滤别名：

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
于 2013-07-01T14:28:54.500 回答
0

问题是您countf在子查询中定义并尝试在where子句中引用它。相反，您需要as countf在外部选择并使用having子句：

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
于 2013-07-01T14:40:43.743 回答