Question

我遇到了我的查询问题，它正在检索所有对象两次（除了最后一个）我过去两天一直在尝试排序而没有结果，所以我想我可以问这里。先谢谢你。

PS：

我已经取得了进展，如果我在PHPMYADMIN上执行它，则错误来自查询，数据被检索两次。（所以有人可以在查询中发现错误）

$token = ***

$userid = ***

$followingposts = $db->query('
    SELECT
        personal_posts.id, 
        personal_posts.body, 
        personal_posts.posted_at, 
        personal_posts.postimg, 
        personal_posts.likes, 
        users.`username`
    FROM users, personal_posts, followers
    WHERE (
        personal_posts.user_id = followers.user_id
        OR personal_posts.user_id = :userid
    )
    AND users.id = personal_posts.user_id
    AND follower_id = :userid
    ORDER BY personal_posts.posted_at DESC;
    ', array(':userid'=>$userid), array(':userid'=>$userid));
$response = "[";
foreach($followingposts as $post) {
    $response .= "{";
    $response .= '"PostId": '.$post['id'].',';
    $response .= '"PostBody": "'.$post['body'].'",';
    $response .= '"PostedBy": "'.$post['username'].'",';
    $response .= '"PostedAt": "'.$post['posted_at'].'",';
    $response .= '"PostImage": "'.$post['postimg'].'",';
    $response .= '"Likes": '.$post['likes'].'';
    $response .= "},";
}
$response = substr($response, 0, strlen($response)-1);
$response .= "]";
http_response_code(200);
echo $response;

    class DB {
        private $pdo;
        public function __construct() {
                $pdo = new PDO('****');
                $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                $this->pdo = $pdo;
        }
        public function query($query, $params = array()) {
                $statement = $this->pdo->prepare($query);
                $statement->execute($params);
                if (explode(' ', $query)[0] == 'SELECT') {
                $data = $statement->fetchAll(PDO::FETCH_ASSOC);
                return $data;
                }
        }
}

Answer 1

（充分部分回答。）

ANSI连接语法将谓词移出where子句，并使它们更接近表引用。 20多年来，这被认为是SQL查询中的最佳实践。是时候停止在from子句中使用逗号了，并明确表格如何连接在一起。 E.g。

SELECT
    personal_posts.id, 
    personal_posts.body, 
    personal_posts.posted_at, 
    personal_posts.postimg, 
    personal_posts.likes, 
    users.`username`
FROM users
INNER JOIN personal_posts ON users.id = personal_posts.user_id
LEFT OUTER JOIN followers ON personal_posts.user_id = followers.user_id
WHERE personal_posts.user_id = :userid
ORDER BY personal_posts.posted_at DESC;

注意我不确定上述查询是否是确切的替换

我的请求是两次重复数据

1 个答案: