Question

我在foreach循环中遇到mysqli_query时遇到问题，我首先从表中获取一个字符串，然后将其分成一个数组。然后我尝试循环遍历数组并在循环内调用查询。

$langs_result = mysqli_query($con, "SELECT Languages FROM users WHERE Username = '$username'");

    $row = mysqli_fetch_assoc($langs_result);

    $langs = $row['Languages'];
    $userLangs = str_replace(" ","",$langs);
    $userLangs = explode(",",$langs);
    print_r($userLangs);
    $posts = array();

    foreach($userLangs as $lang){
        echo "$lang <br>";
        $sql = "SELECT * FROM posts WHERE Language = '$lang'";
        $getLangPosts = mysqli_query($con, $sql);
        array_push($posts, mysqli_fetch_assoc($getLangPosts));
    }

    print_r($posts);

对于这个用户，langusges是德语，意大利语，丹麦语和英语，但$posts数组只包含从第一语言（德语）找到的第一个帖子，任何人都可以帮忙吗？我正在尝试获取$userLangs数组中每种语言的所有帖子。

它正好经过foreach循环，因为每次回显的$lang变量都会发生变化，但查询仍无法正常工作。

感谢您的帮助！

Answer 1

select posts.* from posts
left join users on users.language=posts.language
where users.username='your_desiredusername'
group by users.language;

只需尝试通过填写用户名将其作为单个查询运行无需多次查询

Answer 2

您需要循环内部查询以获取列数据

foreach($userLangs as $lang){
        echo "$lang <br>";
        $sql = "SELECT * FROM posts WHERE Language = '$lang'";
        $getLangPosts = mysqli_query($con, $sql);

        while($row1 = mysqli_fetch_assoc($getLangPosts))
              array_push($posts, $row1['YOUR_COLUMN_NAME']);
    }

或者你应该使用IN子句而不是loop

$langs_result = mysqli_query($con, "SELECT Languages FROM users WHERE Username = '$username'");

while($row = mysqli_fetch_assoc($langs_result)){

$langs = $row['Languages'];
$userLangs = str_replace(" ","",$langs);
$userLangs = explode(",",$langs);
print_r($userLangs);
$posts = array();

$sql = "SELECT * FROM posts WHERE Language IN ('".implode(',',$userLangs)."')";
        $getLangPosts = mysqli_query($con, $sql);

        while($row1 = mysqli_fetch_assoc($getLangPosts))
              array_push($posts, $row1['YOUR_COLUMN_NAME']);
 }

Answer 3

mysqli_fetch_assoc只在每次调用时获取一行，您需要使用它，如下所示：

while ($row_new = mysqli_fetch_assoc($getLangPosts)){
   array_push($posts, $row_new);
}

foreq循环中的Mysqli_query

3 个答案: