嵌套的While循环for mysql_fetch_array没有像我预期的那样工作

Question

我正在尝试为我的网站制作feed系统，其中我使用mysql_fetch_array系统从数据库中获取数据，并为mysql_fetch_array创建了一个while循环，在该循环中，我再次重复了相同的事情，另一个while循环，但问题是嵌套的while循环只执行一次，并且不重复行……这是我用过的一些函数和面向对象的代码，但是你会明白重点是什么！我想到了一个替代方案，但还没有尝试过vaz，我只想用这种方式，即使用for循环而不是while循环，这可能会起作用……

public function get_feeds_from_my_friends(){
    global $Friends;
    global $User;
    $friend_list = $Friends->create_friend_list_ids();
    $sql = "SELECT feeds.id, feeds.user_id, feeds.post, feeds.date FROM feeds WHERE feeds.user_id IN (". $friend_list. ") ORDER BY feeds.id DESC";
    $result = mysql_query($sql);
    while ($rows = mysql_fetch_array($result)) {
            $id = $rows['user_id'];
            $dp = $User->user_detail_by_id($id, "dp");
            $user_name = $User->full_name_by_id($id);
            $post_id = $rows['id'];

            $final_result = "<div class=\"sharedItem\">";
            $final_result .= "<div class=\"item\">";
            $final_result .= "<div class=\"imageHolder\"><img src=\"". $dp ."\" class=\"profilePicture\" /></div>";
            $final_result .= "<div class=\"txtHolder\">";
            $final_result .= "<div class=\"username\"> " . $user_name  . "</div>";
            $final_result .= "<div class=\"userfeed\"> " . $rows['post'] . "</div>";
            $final_result .= "<div class=\"details\">" . $rows['date'] . "</div>";
            $final_result .= "</div></div>";
            $final_result .= $this->get_comments_for_feed($post_id);
            $final_result .= "</div>";

            echo $final_result;
        }
}

public function get_comments_for_feed($feed_id){
    global $User;

    $sql = "SELECT feeds.comments FROM feeds WHERE feeds.id = " . $feed_id . " LIMIT 1";
    $result = mysql_query($sql);
    $result = mysql_fetch_array($result); 
    $result = $result['comments'];
    $comment_list = get_array_string_from_feild($result);

    $sql = "SELECT comment_feed.user_id, comment_feed.comment, comment_feed.date FROM comment_feed ";
    $sql .= "WHERE comment_feed.id IN(" . $comment_list . ") ORDER BY comment_feed.date DESC";
    $result = mysql_query($sql);
    if(empty($result)){ return "";}
    else {
        while ($rows = mysql_fetch_array($result)) {
                $id = $rows['user_id'];
                $dp = $User->user_detail_by_id($id, "dp");
                $user_name = $User->full_name_by_id($id);
                return "<div class=\"comments\"><div class=\"imageHolder\"><img src=\"". $dp ."\" class=\"profilePicture\" /></div>
                            <div class=\"txtHolder\">
                                <div class=\"username\"> " . $user_name  . "</div>
                                <div class=\"userfeed\"> " . $rows['comment'] . "</div>
                                <div class=\"details\">" . $rows['date'] . "</div>
                            </div></div>";

        }       

    }
}

Answer 1

这是因为您使用的是return，它会停止函数的进一步执行。你想要做的是

//...
else {
    $out = '';
    while ($rows = mysql_fetch_array($result)) {
            $id = $rows['user_id'];
            $dp = $User->user_detail_by_id($id, "dp");
            $user_name = $User->full_name_by_id($id);
            $out .= "<div class=\"comments\"><div class=\"imageHolder\"><img src=\"". $dp ."\" class=\"profilePicture\" /></div>
                        <div class=\"txtHolder\">
                            <div class=\"username\"> " . $user_name  . "</div>
                            <div class=\"userfeed\"> " . $rows['comment'] . "</div>
                            <div class=\"details\">" . $rows['date'] . "</div>
                        </div></div>";

    }
    return $out;

}

Answer 2

内部循环在循环的第一次迭代中返回。你确定你应该循环吗？如果你确定它总是第一行，为什么不直接抓住第一行呢？

Answer 3

永远不要使用嵌套的while循环，它不会给出您期望的结果。按照以下方式操作，就像我在此脚本中所做的那样：

<?php 
include('dbconnect.php');

$query = "SELECT * FROM tiles_categories" . " LIMIT 0, 3" ;
$result = mysql_query($query) or die(mysql_error()); 

while($row = mysql_fetch_array($result)) {  $category_id = $row["cat_id"] ;
echo "<div class='product'>";
            echo "<h2 style='padding-bottom:10px; color:#6F0D00;'>". $row['cat_name'] . "</h2>";
            gettiles($category_id);
        echo"</div>";
    }

    function gettiles($category_id) {
        $tiles_query = "SELECT * FROM tiles_info where cat_id = '".$category_id."'";
        $result = mysql_query($tiles_query) or die(mysql_error());
        while($row_tiles = mysql_fetch_array($result)) {
            echo "<div align='center' style='float:left; width:100px; margin:0px 35px 0px 0px;'>";

            echo "</div>";
        }
    }
?>