Issues with mySQLi and PHP - php

Question

I'm trying to create a internal messaging system.
My code is below:
$useraccess = $loggedInUser->username;
$sql = "SELECT id, user_name FROM ".$db_table_prefix."users WHERE user_name='$useraccess'";
$query = $mysqli->query($sql) or die ("Error");
while ($row = mysqli_fetch_array($query)) {
$pid = $row["id"];
$username = $row["user_name"];
}
$query->close();
$sqlCommand = "SELECT COUNT(id) AS numbers FROM ".$db_table_prefix."messages_inbox WHERE userid='$pid'";
$query = $mysqli->query($sql) or die ("Error");
$result = mysqli_fetch_assoc($query);
$inboxMessages = $result['numbers'];
?>
<h1>Inbox</h1>
<?php
$sql="SELECT * FROM ".$db_table_prefix."messages_inbox WHERE userid='$pid' ORDER by id DESC";
$result=$mysqli->query($sql);
$count=mysqli_stmt_num_rows($result);
?>
<p>
<table width="500" border="0" cellspacing="0" cellpadding="0">
<tr>
<th style="text-align: left; ">Title</th>
<th style="text-align: right; ">Sender</th>
<th style="text-align: right; "><b>Actions</b></th>
</tr>
<?php
while($rows=mysqli_field_count($result)) {
?>
<?php if ($rows['viewed'] == 0) { // show messages in bold?>
<tr>
<td style="text-align: left; "><b><?php echo $rows['title']; ?></b></td>
<td style="text-align: right; "><?php echo $rows['from_username']; ?></td>
<td style="text-align: right; ">Delete</td>
</tr>
<?php } else if ($rows['viewed'] == 1) { ?>
<tr>
<td style="text-align: left; "><?php echo $rows['title']; ?></td>
<td style="text-align: right; "><?php echo $rows['from_username']; ?></td>
<td style="text-align: right; ">Delete</td>
</tr>
<?php } ?>
<?php } ?>
</table>
<?php if ($inboxMessages > 0) { ?>
<?php } else
{ print "<div id=\"errors\">Currently you do not have messages in your Inbox</div>";
} ?>
This is the inbox in which I'm trying to show data from the DB. It connects no problem otherwise it would throw up the Error, so I believe it's my syntax.
I receive the following errors.
Warning: mysqli_stmt_num_rows() expects parameter 1 to be mysqli_stmt, object given in /opt/lampp/htdocs/project/inbox.php on line 28
Warning: mysqli_field_count() expects parameter 1 to be mysqli, object given in /opt/lampp/htdocs/project/inbox.php on line 38
Notice: Undefined index: numbers in /opt/lampp/htdocs/project/inbox.php on line 20

Answer 1

Use mysqli_num_rows instead, as follows:
$count=mysqli_num_rows($result);
Reference documentation: http://php.net/manual/en/mysqli-result.num-rows.php
To use mysqli_stmt_num_rows you need to change a few lines from what you have:
$sql="SELECT * FROM ".$db_table_prefix."messages_inbox WHERE userid='$pid' ORDER by id DESC";
if ($stmt = $mysqli->prepare($sql)) {
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
$count = mysqli_stmt_num_rows($stmt)
$stmt->close();
}
And here is the documentation for mysqli_stmt_num_rows: http://php.net/manual/en/mysqli-stmt.num-rows.php