選擇從第一個表中的一行，然後加入多個

Question

我有以下表格，

客戶

client_id | client_name 
2   | client 1 
3   | client 2 
4   | client 3 

新聞稿

press_release_id | date     | title     | client_id 
1    | 2012-10-16 00:00:00 | new press release  | 3 
2    | 2012-10-16 00:00:00 | worlwide news   | 2 

新聞稿內容

press_release_id | content | translation 
1    | content | en 
2    | content | fr 

我想寫一個查詢b基本上爲每個客戶選擇最新的新聞稿。這份名單將只返回1個客戶端爲每個新聞稿

萬分感謝

Answer 1

試試這個：

SELECT 
    c.client_name, 
    pr.date, 
    pr.title, 
    pc.content, 
    pc.translation 
FROM clients c 
INNER JOIN pressreleases pr ON c.client_id = pr.client_id 
INNER JOIN 
(
    SELECT 
    press_release_id, MAX(date) LatestDate 
    FROM pressreleases 
    GROUP BY press_relaese_id 
) pl ON pr.press_release_id = pl.press_release_id AND pr.date = pl.latestdate 
INNER JOIN press releasecontent pc ON pr.press_release_id = pc.press_release_id 

Answer 2

SELECT a.*, b.*, d.* 
FROM clients a 
     INNER JOIN pressReleases b 
      ON a.client_ID = b.client_ID 
     INNER JOIN 
     (
      SELECT client_ID, MAX(date) maxDate 
      FROM pressReleases 
      GROUP BY client_ID 
     ) c ON b.date = c.mAxDate AND 
       b.client_ID = c.client_ID 
     INNER JOIN pressReleaseContent d 
      ON b.press_release_id = d.press_release_id 

• SQLFiddle Demo (schema may be different but they have he same thought)
• Previous Answer (browse for maximum record for each entry)