Question

我想在多页上显示评论，所以我想从数据库的1页上选择评论，并在所有其他页面上包括这些评论。

我可以选择并显示每个评论，但是某些帖子没有评论。现在，我在没有评论的情况下收到每个帖子的错误。 Notice: Undefined variable: showComments in ...\comments.php on line 7

选择评论的页面：

class Comment {
          public static function displayComments($postId) {
                  $comments = DB::query('SELECT comments FROM table WHERE post_id=:postid', array(':postid'=>$postId);
                  foreach($comments as $comment) {
                          $showComments[] = $comment['comment'];
                  }
                          return $showComments;//this is line 7
          }
}

其他页面：

$postOutput = "postImg, postLikes, postLikeButton";

if(Comment::displayComments($post['id']) >= 1) {
           $comments = Comment::displayComments($post['id']);
           foreach ($comments as $comment) {
                   $postOutput .= $comment;
           }
}

$postOutput .= "postCommentForm";
echo $postOutput;

Answer 1

在调用它之前定义空数组。当您运行foreach循环时，请检查空状态。现在发生的事情是您没有从查询中获取评论，这就是为什么这样。试试这个。

class Comment {
          public static function displayComments($postId) {
                  $showComments = array(); //this sould be defined in your code
                  $comments = DB::query('SELECT comments FROM table WHERE post_id=:postid', array(':postid'=>$postId);
              if(!empty($comments)){ //check not empty condition.

                  foreach($comments as $comment) {
                          $showComments[] = $comment['comment'];
                  }
              }
          return $showComments;//this is line 7
          }
}

PHP从数据库中选择并返回值

1 个答案: