can i use while loop inside another while loop in php - php

Question

I'm creating a comment system in my project. I want each posted question to have a comment. I was able to post the comment, but I am having a problem displaying all comment to it's respective answers. I was able to display only one row but not the row of the comment. I try to use a while loop nested inside the while that echo's each question, but it hangs. When I use if it only displays the first row of the comment of each question.
So my question is how can I display them all?
<div class="answer">
<?php
include 'db.php';
$sql = "select * from answers where questionrid IN(select id from question where id='$qid')";
$result = mysqli_query($con,$sql);
if($result){
while($ro = mysqli_fetch_assoc($result)){
?>
<div class="a_view">
<pre>
<?php
echo $ro["answer"];
?>
</pre>
</div>
<div class="ans_comment">
<?php
if($ro["id"]){
$id = $ro["id"];
$sqli = "SELECT * FROM comments WHERE answerid='$id'";
$query = mysqli_query($con,$sqli);
$row = mysqli_fetch_assoc($query);
$num = mysqli_num_rows($query);
while($row){
?>
<div><?php echo $row["comments"];?></div>
<?php
}
}
?>
</div>
<div class="add"><div class="coment">add a comment</div> <div id="coment">
<form class="cform" method="post" action="acomment.php">
<textarea type="text" name="comment" class="tcomment" placeholder="add your comment here,your is
required to give correction or more information about the problem"></textarea><br><br>
<input type="hidden" value="<?php echo $ro["id"]; ?>" name="userid">
<input type="submit" value="Post your comment">
</form>
</div></div>
<?php
}
}else{
echo "no record";
}
?>
<?php
$con->close();
?>
This is the section that made it hang
while($row){
?>
<div><?php echo $row["comments"];?></div>
<?php
}
when I use if, it only echos one row.

Answer 1

Instead of
while($row){
do it just like you're doing in the while loop above
while($row = mysqli_fetch_assoc($query)){
The way you have it now, $row is never changing, and therefore always evaluates to true, leaving you stuck in your loop.