比较2个集

Question

当找到独特的价值观，我有以下表，versiontrim叫，一些样本数据：

version_id trim_id 
    410  3 
    410  5 
    410  10 
    410  15 
    410  20 
    411  2 
    411  5 
    411  15 
    411  25 
    411  28 

另一个表，修剪，保持每个trim_id的细节，比如如下：

trim_id trim 
    2  Air conditioner auto    
    3  Air conditioner manual 
    5  Airbag 
    10  Cloth seats 
    25  Leather seats 
    etc..... 

我正在为每个SET 2的version_id提取唯一的trim_id。结果应该看起来像如下：

version_id trim_id trim     version_id trim_id  trim 
              411   2   Air conditioner auto 
410  3  Air conditioner manual 
410  10  Cloth seats 
              411   25  Leather seats 
410  20  blahblah 
              411   28   blah.... 
etc... 

我还是设法得到每个单独设置使用下面的查询，交换的VERSION_ID的：

SELECT version_id, trim_id, trim 
FROM versiontrim a 
INNER JOIN trims USING(trim_id) 
WHERE a.version_id = 411 
AND NOT EXISTS 
(
SELECT * FROM versiontrim b 
INNER JOIN trims USING(trim_id) 
WHERE a.trim_id = b.trim_id 
AND b.version_id = 410 
) 

我相信还有一个更简单的方法来做到这一点，有只是一个查询，以便我可以正确输出它。 感谢您的帮助。

Answer 1

SELECT 
    CASE 
    WHEN v.version_id = 410 THEN v.version_id 
    ELSE '' 
    END AS Left_Version 
    ,CASE 
    WHEN v.version_id = 410 THEN v.trim_id 
    ELSE '' 
    END AS Left_Trim_id 
    ,CASE 
    WHEN v.version_id = 410 THEN t.trim 
    ELSE '' 
    END AS Left_Trim 
    ,CASE 
    WHEN v.version_id = 411 THEN v.version_id 
    ELSE '' 
    END AS Right_Version 
    ,CASE 
    WHEN v.version_id = 411 THEN v.trim_id 
    ELSE '' 
    END AS Right_Trim_id 
    ,CASE 
    WHEN v.version_id = 411 THEN t.trim 
    ELSE '' 
    END AS Right_Trim 
FROM(SELECT trim_id, COUNT(*) 
    FROM versiontrim 
    WHERE version_id IN (410,411) 
    GROUP BY trim_id 
    HAVING COUNT(*) = 1) AS vt 
JOIN versiontrim AS v 
ON v.trim_id = vt.trim_id 
    AND v.version_id IN (410,411) 
JOIN trims AS t 
ON v.trim_id = t.trim_id 
GROUP BY v.trim_id 
ORDER BY v.trim_id; 

Answer 2

试试这个::

Select 
version_id, trim_id, trim 
FROM versiontrim a 
INNER JOIN trims t on (a.trim_id=t.trim_id) 
GROUP BY a.version_id, t.trim_id