script(while-loop) stops and has no ouput when mul

I want to select more than one columns from TABLE but the script is not working once the while loop starts. my php and html code is:

<table border="0">
include_once $_SERVER['DOCUMENT_ROOT'].'/include/db.inc.php' ;
$sql="select post_title,post_desc,post_date,course,semester,firstname,lastname 
      FROM wbut_forum_posts left join users on post_by = email
      ORDER BY post_id DESC LIMIT 25";
$result = mysqli_query($link,$sql );

if (!$result) {
    include_once "wall.html.php";
    echo'<tr><td align="center"> OOOOPPPPPSSS!!!SORRY,UNABLE TO DISPLAY LATEST 25 TOPICS</td></tr>';
    exit();
}

while ($row = mysqli_fetch_array($result)) {
    $titles[] = $row['post_title'];
    $descs[] = $row['post_desc'];
    $dates[] = $row['post_date'];
    $courses[] = $row['course'];
    $semesters[] = $row['semester'];
    $firstnames[] = $row['firstname'];
    $lastnames[] = $row['lastname'];
}

$cnt=0;
foreach ($titles as $x) {
    $title[$cnt]=$x;
    $cnt=$cnt+1;
}

$cnt=0;
foreach ($firstnames as $x) {
    $firstname[$cnt]=$x;
    $cnt=$cnt+1;
}

$cnt=0;
foreach ($lastnames as $x) {
    $lastname[$cnt]=$x;
    $cnt=$cnt+1;
}

$cnt=0;
foreach ($descs as $x) {
    $descs[$cnt]=$x;
    $cnt=$cnt+1;
}

$cnt=0;
foreach ($dates as $x) {
    $date[$cnt]=$x;
    $cnt=$cnt+1;
}

$cnt=0;
foreach ($courses as $x) {
    $courses[$cnt]=$x;
    $cnt=$cnt+1;
}

$cnt=0;
foreach ($semesters as $x) {
    $semester[$cnt]=$x;
    $cnt=$cnt+1;
}

echo'AFTER FOREACHES';
for ($i=0;$i<$cnt;$i=$i+1) {

    echo'<table border="0">';
        echo'<tr>';
            echo '<td align="left"><span class="style1">';
                echo $firstname[$i] . " " . $lastname[$i] ;
            echo '</span></td>';
            echo '<td align="center"  colspan="2">RELATED COURSE :';
                echo $course[$i];
                echo '&nbsp;&nbsp;&nbsp;&nbsp; RELATED SEMESTER:';
                echo $semester[$i];
            echo '</td>';
        echo '</tr>';
        echo '<tr>';
            echo '<td>&nbsp;</td>';
            echo'<td align="left"><span class="style3">';
                echo  $desc[$i];
            echo '</span></td>';
            echo'<td valign="baseline">';
                echo $date[$i];
            echo '</td>';
        echo '</tr>';
        echo'<tr>';
            echo '<td>&nbsp;</td>';
            echo '<td align="left" background="reply_bg.gif"><span class="style3">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;';
                echo 'echo the replies here';
                echo '</span>';
            echo '</td>';
            echo'<td>&nbsp;</td>';
        echo '</tr>';
        echo '<tr>';
            echo '<td>&nbsp;</td>';
            echo '<form action="reply.html.php" method="post"><td align="left" ><textarea rows="5" cols="40" name="reply" id="reply"></textarea>    </td><td valign="baseline"><input type="submit" name="asd" value="REPLY" /><input type="hidden" name="reply" value="reply" /></td></form>';
        echo '  </tr>';
        echo '</table>';        
    }
    echo' CLOSING MAIN FOR ';
?>
</table>

note 1:not working..I have echoed in various place. What I noticed it exactly stops while the while loop starts

回答1:

After the variable $sql, where is $result?
$result = mysql_query($sql) **or die(mysql_error)** // to give the output error from MySQL if there is any
Before the while, use either var_dump($row), or print_r($row).
If you encounter blank pages or no error reporting, use error_reporting(E_ALL); at he beginning of your script.

Edit: Sorry, you're using MySQLi. Use $mysqli->error.

回答2:

You have no opening PHP tag on the first line of your code. It should be: