使用UNIONS和GROUP BY的SQL查询

Question

查询:

SELECT max(image_url), Model_Name
FROM (
    SELECT max(image_url), Model_Name
    FROM dbo.proinfo_vodafone WHERE Brand_name='Nokia'
    UNION
    SELECT max(image_url), Model_Name
    FROM dbo.proinfo_3 WHERE Brand_name='Nokia' 
    UNION
    SELECT max(image_url), Model_Name
    FROM dbo.proinfo_t WHERE Brand_name='Nokia'
    UNION
    SELECT max(image_url), Model_Name
    FROM dbo.proinfo_o2 WHERE Brand_name='Nokia'
    UNION
    SELECT max(image_url), Model_Name 
    FROM dbo.proinfo_orange
    WHERE Brand_name='Nokia') AS temp
WHERE Model_Name IS NOT NULL
GROUP BY Model_Name
ORDER BY Model_name ASC

给出错误:Msg 8155,Level 16,State 2,Line 3没有为'temp'的第1列指定列.

现在,说实话我不擅长SQL,我在类似的查询中使用Quick Replace进行了这个查询,我似乎无法理解查询有什么问题.

请帮忙!提前致谢.

Anchit

Answer 1

  SELECT MAX(image_url), Model_Name
  FROM   (SELECT MAX(image_url) image_url, Model_Name
           FROM   dbo.proinfo_vodafone
           WHERE  Brand_name = 'Nokia'
           UNION
           SELECT MAX(image_url) image_url, Model_Name
           FROM   dbo.proinfo_3
           WHERE  Brand_name = 'Nokia'
           UNION
           SELECT MAX(image_url) image_url, Model_Name
           FROM   dbo.proinfo_t
           WHERE  Brand_name = 'Nokia'
           UNION
           SELECT MAX(image_url) image_url, Model_Name
           FROM   dbo.proinfo_o2
           WHERE  Brand_name = 'Nokia'
           UNION
           SELECT MAX(image_url) image_url, Model_Name
           FROM   dbo.proinfo_orange
           WHERE  Brand_name = 'Nokia') AS temp
  WHERE  Model_Name IS NOT NULL
  GROUP  BY Model_Name
  ORDER  BY Model_name ASC