php从多个表中选择reords并比较结果

Question

第一个语句选择用户正在关注的所有用户，第二个语句选择用户的所有注释以及他们关注的所有其他用户，我正在尝试组合两个select语句：

$get_user = $user_data['username']; $get_following = mysqli_query($con,"SELECT * FROM follows WHEREfollower= '$get_user' ")

$query = mysqli_query($con,"SELECT * FROM posts WHERE username = '$followe' OR username = '$get_user' ORDER BY date_added DESC LIMIT 0,5 ");

我尝试使用以下代码，但只有当用户使用的用户超过人时才会提取单个用户：

$get_following = mysqli_query($con,"SELECT * FROM follows WHEREfollower= '$get_user' ");

$ffg = mysqli_fetch_assoc($get_following);

$ff = $ffg['follower'];

$query = mysqli_query($con,"SELECT * FROM posts WHERE username = '$ff' OR username = '$get_user' ORDER BY date_added DESC LIMIT 0,5 ");

请帮助解决这个问题，谢谢。