MySQL查詢選擇與條件及加入

Question

我有這3和表（這些結構）：

 outreach 
     id url    profile_id 
------------------------------------------ 
     40 www.google.com  2 
     41 www.yahoo.com  3 
     42 www.test.com  1 

     outreach_links 
     id outreach_id end_date   status 
    ----------------------------------------------- 
     1 41   2016-01-12  Pending 
     2 40   2016-03-12  Pending 
     3 40   2016-02-12  Approved 

     comments 
     id outreach_id name 
    ---------------------------- 
     1 40 
     2 40 
     3 40 

，我有這個疑問：

select o.*, 
SUM(if(ol.status = "Approved" and (ol.end_date > now() or end_date is null), 1, 0)) as cond1, 
SUM(if(ol.status = "Pending" and (ol.end_date != now() or end_date is null), 1, 0)) as cond2, 
SUM(if(ol.status = "Pending" and (ol.end_date < now()), 1, 0)) as cond3 
from outreach o 
left join outreach_links ol on ol.outreach_id = o.id 
where o.profile_id=2 
group by o.id 
having (cond1 = 0 and cond2 = 0) or (cond1 = 0 and (cond2 = 1 and cond3 >=1)) order by ol.end_date desc 

我試圖解決這一問題的查詢，並它還選擇以下內容：

1). ol.* ONLY if MAX(end_date) and 
2). Count(id.comment) count all comments for that particular row 

是否有可能？

現在這裏是輸出

+"id": "40" 
+"profile_id": "2" 
+"url": "http://www.google.com" 
+"created_at": "2016-12-05 21:55:10" 
+"updated_at": "2016-12-05 22:49:56" 
+"cond1": "0" 
+"cond2": "0" 
+"cond3": "5" 

我想補充

+"max_date": get me max of end_date and the whole row of the row highlighted 
+"Count(comments)": get me all the comments count for this one which is 3 

感謝

Answer 1

你想獲得最新的更新日期？以下查詢應該爲您提供最新的更新日期。

但是，我不明白你想要得到的cond1，cond2，cond3和什麼應該填充爲created_date和updated_date？你可以給這些領域的定義嗎？

SELECT o.*, ol.*, COUNT(c.id) 
FROM outreach o 
LEFT JOIN outreach_links ol ON ol.outreach_id = o.id 
LEFT JOIN comments c ON c.outreach_id = o.id 
WHERE ol.id = (SELECT ol2.id 
       FROM outreach_links ol2 
       WHERE ol2.outreach_id = ol.outreach_id    
       ORDER BY ol2.end_date, ol2.id DESC 
       LIMIT 1) 
     OR ol.id IS NULL 
GROUP BY o.id, ol.id