如何內部聯接三個表並獲得計數

Question

我有三個表：

members (id, name, surname, usr_img)

user_uploads (imgID, user_id, filename, description, up_time)

img_likes (likeID, img_id, user_id)

我需要從user_uploads中獲取所有信息，並使用img_id從成員中獲取上傳者信息，並在img_likes表中進行2個計數（檢查user_id（來自會話變量）和img_id是否存在，並獲得img的總贊數）。

SELECT user_uploads.* AS uu, members.*, COUNT(img_id, user_id) AS usr_liked, COUNT(img_id) AS total_likes
FROM user_uploads
INNER JOIN members AS m ON m.id = uu.user_id -- owner info
INNER JOIN img_likes AS il ON il.img_id = uu.imgID AND il.user_id = ? -- check if logged in user already liked
INNER JOIN img_likes AS ilt ON ilt.img_id = uu.imgID -- total likes
GROUP BY img_id, user_id
ORDER BY up_time DESC

我不需要從img_id中得到任何信息，只需計算行數即可。 我不知道是否需要內部聯接，也許要指定user_id？

並獲得計數：

$usr_liked = row['usr_liked'];
$total_likes = rwo['total_likes'];

那行得通嗎？

編輯：添加新查詢：

SELECT
    user_uploads.*,
    (
        SELECT *
        FROM members m
        WHERE m.id = user_uploads.user_id
    ),
    (
        SELECT COUNT(*)
        FROM img_likes t
        WHERE t.img_id = user_uploads.imgID AND t.user_id = ?
    ) AS user_likes,
    (
        SELECT COUNT(*)
        FROM img_likes t
        WHERE t.img_id = user_uploads.imgID
    ) AS total_likes
FROM user_uploads
ORDER BY up_time DESC

Answer 1

您可以使用子查詢：

SELECT 
    uu.*, 
    m.*,
    (
        SELECT COUNT(t.*)
        FROM img_likes t
        WHERE t.img_id = uu.imgID AND t.user_id = ?
    ) AS user_likes,
    (
        SELECT COUNT(t.*)
        FROM img_likes t
        WHERE t.img_id = uu.imgID 
    ) AS total_likes
FROM 
    user_uploads AS uu
    INNER JOIN members AS m ON 
        m.id = uu.user_id
ORDER BY
    uu.up_time DESC