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我使用下面的查詢和用PHP編寫的子查詢。發生如果一個子查詢爲空,則Mysql查詢返回空值
$query = mysqli_query($mysqli, "select
users.id as id,
users.display_name as display_name,
users.user_code as user_code,
(select count(articles.id) from articles where articles.user_code = '$user_code') as user_article_count,
(select count(comments.id) from comments where comments.user_code = '$user_code') as user_comment_count
from users");
我的問題,只要子查詢的一個不匹配任何行,整個查詢返回空值,而不是返回null只是user_article_count或user_comment_count。
我該如何避免這種情況?