另一个SQL语句我不明白

Question

我知道答案，我的问题有什么做的排名，只是不知道该怎么做完全是。我的发言目标是只获得5条记录，但优先考虑某个表格上的记录而非另一个表格。

我有两个表：News和NewsToLocation。

让我们假设有在新闻台4个新闻和3在满足我的要求的NewsToLocation。因为我只能选择5我要确保在News表中4得到的偏好，然后只从NewsToLocation表中选择1。我目前的查询是做相反的，我不知道如何解决它。

这里是整个查询。

SELECT 
newSpotlights.* 
FROM 
(SELECT 
    TOP 5 n.news_id, 
    n.is_spotlight, 
    n.location_id, 
    n.news_title, 
    CAST(n.news_content AS varchar(200)) AS news_content, 
    n.writing_date, 
    n.publication_date, 
    n.end_date, 
    n.alt_uri, 
    n.youtube_code, 
    n.icon_img_file, 
    n.banner_img_file 
FROM 
    (SELECT 
     n.news_id 
    FROM rcde_news n 
    WHERE n.location_id = 4 
    AND n.is_spotlight = 1 AND n.publication_date < GETDATE() AND n.end_date > GETDATE() 
    AND n.status_id = 2 /*2 = Active rcde_ItemStatus*/ 
    UNION 
    SELECT 
     n.news_id 
    FROM rcde_newsToLocation ntl 
    INNER JOIN rcde_news n ON ntl.news_id = n.news_id 
    WHERE ntl.location_id = 4 
    AND n.status_id = 2 /*2 = Active rcde_ItemStatus*/ 
    ) AS News 
INNER JOIN rcde_news n ON news.news_id = n.news_id 
WHERE n.is_spotlight = 1 
AND n.publication_date < GETDATE() 
AND n.end_date > GETDATE() 
ORDER BY publication_date DESC 
) AS newSpotlights 

我觉得我应该可以做一些排序最内在的查询排序，但我不知道该怎么做。我有点明白排名，但不知道我会怎么做一个UNION声明。我可以做一些简单的事情，比如在联盟的不同部分分别选择1作为等级和2作为等级，然后按等级排序？

Answer 1

您只需添加1秩，2秩到查询的联合部分，然后进行排序，最后第一。

SELECT 
    TOP 5 
    n.news_id, 
    n.is_spotlight, 
    n.location_id, 
    n.news_title, 
    CAST(n.news_content AS varchar(200)) AS news_content, 
    n.writing_date, 
    n.publication_date, 
    n.end_date, 
    n.alt_uri, 
    n.youtube_code, 
    n.icon_img_file, 
    n.banner_img_file 
FROM 
    (SELECT 
     1 as rank, 
     n.news_id 
    FROM rcde_news n 
    WHERE n.location_id = 4 
    AND n.is_spotlight = 1 AND n.publication_date < GETDATE() AND n.end_date > GETDATE() 
    AND n.status_id = 2 /*2 = Active rcde_ItemStatus*/ 
    UNION 
    SELECT 
     2 as rank, 
     n.news_id 
    FROM rcde_newsToLocation ntl 
    INNER JOIN rcde_news n ON ntl.news_id = n.news_id 
    WHERE ntl.location_id = 4 
    AND n.status_id = 2 /*2 = Active rcde_ItemStatus*/ 
    ) AS News 
INNER JOIN rcde_news n ON news.news_id = n.news_id 
WHERE n.is_spotlight = 1 
AND n.publication_date < GETDATE() 
AND n.end_date > GETDATE() 
ORDER BY rank DESC, publication_date DESC 

Answer 2

是的，你基本上就和您的等级观念：

select top 5 Column1, Column2 
from (
    select top 5 Column1, Column2, 1 as Rank 
    from News 
    order by SomeColumn 

    union all 

    select top 5 Column1, Column2, 2 as Rank 
    from NewsLocation 
    order by SomeColumn 
    ) x 
order by Rank 

Answer 3

SELECT 
    TOP 5 
    n.news_id 
FROM 
    (SELECT 
     1 as ranking, 
     n.news_id 
    FROM rcde_news n 
    WHERE blah blah 
    UNION 
    SELECT 
     2 as ranking, 
     n.news_id 
    FROM rcde_newsToLocation ntl 
    WHERE blah blah 

    ) AS News 
ORDER BY publication_date DESC, Ranking