MYSQL - 加入三個表

Question

我有這個數據庫：

Image : id,user_id,[..],created_at 
Visit : id,image_id,created_at 
user : id,[..] 

，我有這個疑問讓高層上傳用戶，

$current_month = date('Y-m-d', strtotime("first day of this month")) . ' 23:59:59'; 
$users = DB::query("SELECT * , 
     COUNT(p.id) as numPics 
    FROM 
     images p 
    INNER JOIN 
     users u 
    ON 
    p.user_id = u.id 
    WHERE 
    p.created_at >= \"$current_month\" 
    GROUP BY p.user_id 
    ORDER BY numPics DESC LIMIT 10"); 

我有什麼是joing訪問表，所以我可以在當前月份獲得每幅圖像的總體勝率。

Answer 1

不知道您的訪問表的結構，我不能給出具體的細節，但你應該能夠在JOIN後添加JOIN子句訪問用戶：

SELECT *, COUNT(p.id) as numPics, COUNT(v.id) as numVisits 
FROM images p 
INNER JOIN users u ON p.user_id = u.id 
LEFT JOIN visits v ON v.image_id = p.id AND v.created_at >= "$current_month" 
WHERE p.created_at >= "$current_month" 
GROUP BY p.user_id 
ORDER BY numPics DESC LIMIT 10 

Answer 2

假設你有一個在訪問表image_id領域：

SELECT * , 
    COUNT(p.id) as numPics 
FROM 
    images p 
INNER JOIN 
    users u 
ON 
    p.user_id = u.id 

    INNER JOIN visits as v ON v.image_id = p.id 

WHERE 
p.created_at >= \"$current_month\" 
GROUP BY p.user_id 
ORDER BY numPics DESC LIMIT 10"