php - 如果没有找到行，MySQL make count 不返回任何内容

Question

I'm trying to use a count in my MySQL query to count the amount of rows with a matching column, and the query is working, however when the select query the count is being used in returns no rows, the count value仍然返回 0，因此查询将返回一个空行，但计数列除外，该列具有 0。

这是我的查询:

SELECT
    forum_threads_forums.id,
    forum_threads.title,
    forum_threads.description,
    forum_threads.views,
    COUNT(DISTINCT forum_posts_threads.post_id) AS post_count,
    users.id AS user_id,
    users.username AS user_username
FROM
    forum_threads
INNER JOIN
    forum_threads_forums
ON
    forum_threads.id=forum_threads_forums.thread_id
AND
    forum_threads_forums.forum_id=:forum_id
LEFT OUTER JOIN
    forum_posts_threads
ON
    forum_posts_threads.thread_id=forum_threads_forums.thread_id
INNER JOIN
    users
ON
    forum_threads.user_id=users.id

When the select query doesn't return any rows, the count still does.所以我得到这样的结果:

id  title   description views   post_count  user_id user_username
                                0

我希望它不返回任何内容，这样我就可以用 PHP 可靠地计算结果。

有没有人知道如何实现这一点？我迷路了。

提前感谢您的帮助。

Answer 1

添加:

HAVING post_count > 0

到查询结束。

如果有任何匹配项，它将返回 1 行，post_count 将包含不同帖子的数量，如果没有匹配项，则返回 0 行。