Mysqli num row返回不起作用(Mysqli num row returned is not working)

 我想知道为什么它不适用于mysqli eventhou mysql_num_row正在工作。 
 
if (mysql_num_rows($rows) > 0) {
    echo "<p>That name has been taken </p>";
}
 
 那是mysql。 但是，我试图将其转换为mysqli。 
 
 if (mysqli_num_rows($rows) > 0) {
        echo "<p>That name has been taken </p>";
    }
 
 它应该显示在屏幕上，但事实并非如此。 并且没有显示任何错误消息。 或者我错过了什么？ 有任何想法吗？ 

I'm wondering why it is not working for mysqli eventhou mysql_num_row is working. 
 
if (mysql_num_rows($rows) > 0) {
    echo "<p>That name has been taken </p>";
}
 
That is mysql. But, Im trying convert it to mysqli.
 
 if (mysqli_num_rows($rows) > 0) {
        echo "<p>That name has been taken </p>";
    }
 
It supposed to be displayed on the screen but it's not. And there is nothing error message displayed. Or am I missing something? Any ideas?

原文：https://stackoverflow.com/questions/21472691