Question

工作查询

(   SELECT R.ref as ref, 
           R.field8, 
           R.file_extension, 
           DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, 
           Ra.rank as rank 
    FROM resource R 
    INNER  JOIN resource_ranking Ra ON R.ref = Ra.ref_id 
    ORDER BY Ra.rank limit 2
) 
UNION ALL
(   SELECT R.ref as ref, 
           R.field8, 
           R.file_extension, 
           DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, 
           '99' as rank  
    FROM resource R
    LEFT JOIN (
           SELECT ref_id 
           FROM resource_ranking 
           ORDER BY rank LIMIT 2
    ) AS B ON R.ref = B.ref_id
    INNER JOIN collection_resource C ON R.ref = C.resource
    WHERE B.ref_id IS NULL 
      AND R.ref !=  '-1' AND C.collection = 1 
)
ORDER BY rank ASC, ref DESC LIMIT 0,  8

以上查询工作正常我想使用内部联接

向现有查询添加另一个表

以下是我使用内部联接的书面查询

(   SELECT R.ref as ref, 
           R.field8, 
           R.file_extension, 
           DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, 
           Ra.rank as rank 
    FROM resource R 
    INNER  JOIN resource_ranking Ra ON R.ref = Ra.ref_id 
    ORDER BY Ra.rank limit 2
    INNER  JOIN resource_rating Rr ON R.ref = Rr.resource_id 
    ORDER BY Rr.rating DESC
) 
UNION ALL
(   SELECT R.ref as ref, 
           R.field8, 
           R.file_extension, 
           DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, 
           '99' as rank  
    FROM resource R
    LEFT JOIN (
         SELECT ref_id 
         FROM resource_ranking 
         ORDER BY rank LIMIT 2
    ) AS B ON R.ref = B.ref_id
    INNER JOIN collection_resource C ON R.ref = C.resource
    WHERE B.ref_id IS NULL AND Rr.userid=1 
      AND R.ref !=  '-1' AND C.collection = 1
)
ORDER BY rank ASC, ref DESC LIMIT 0, 8

但是，这会出现以下错误：

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INNER JOIN resource_rating Rr ON R.ref = Rr.resource_id ORDER BY Rr.rating DESC' at line 3

Answer 1

这是你的第一个子查询：

SELECT R.ref as ref, R.field8, R.file_extension,
       DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, Ra.rank as rank
FROM resource R  INNER JOIN
     resource_ranking Ra
     ON R.ref = Ra.ref_id
ORDER BY Ra.rank
limit 2
INNER  JOIN resource_rating Rr ON R.ref = Rr.resource_id ORDER BY Rr.rating DESC)

inner join位置错误。试试这个：

SELECT R.ref as ref, R.field8, R.file_extension,
       DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, Ra.rank as rank
FROM resource R  INNER JOIN
     resource_ranking Ra
     ON R.ref = Ra.ref_id INNER JOIN
     resource_rating Rr
     ON R.ref = Rr.resource_id
ORDER BY Ra.rank
limit 2

我不确定附加的order by条款是什么。

如果您学习格式化查询以使其可读，则可以更轻松地找到语法错误。

Answer 2

在摆脱这个后尝试：

 ORDER BY Ra.rank limit 2

如果您只需要连接中的两行，则将LIMIT 2放在第二行之后。

Answer 3

错误在于：

INNER  JOIN resource_ranking Ra ON R.ref = Ra.ref_id 
ORDER BY Ra.rank limit 2
INNER  JOIN resource_rating Rr ON R.ref = Rr.resource_id 
ORDER BY Rr.rating DESC

SELECT语句只能有一个ORDER BY子句，它必须是语句中的最后一个子句（ORDER BY必须在末尾）：

SELECT ....
FROM table1
JOIN table2 ON ....
JOIN ......
WHERE ...
ORDER BY ...

Answer 4

(SELECT R.ref as ref, R.field8, R.file_extension, Rr.rating, DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, Ra.rank as rank FROM resource R 
    INNER  JOIN resource_ranking Ra ON R.ref = Ra.ref_id 
    INNER JOIN resource_rating Rr ON R.ref = Rr.resource_id
ORDER BY Ra.rank limit 2) 
UNION ALL
    (SELECT R.ref as ref, R.field8, R.file_extension, Rr.rating, DATE_FORMAT(R.creation_date,'%e/%c/%Y') as date, '99' as rank  FROM resource R
    LEFT JOIN (SELECT ref_id FROM resource_ranking ORDER BY rank LIMIT 2) AS B ON R.ref = B.ref_id
    INNER JOIN collection_resource C ON R.ref = C.resource
    INNER JOIN resource_rating Rr ON R.ref = Rr.resource_id
    WHERE B.ref_id IS NULL AND Rr.user_id = 1 
    AND R.ref !=  '-1' AND C.collection = 1)
    ORDER BY rank ASC, ref DESC LIMIT 0, 8

在查询中使用内部联接时出现SQL语法错误

4 个答案: