I'm working on a website for educational use, and I've run in to a little error when I've tried to build a file that does some logic.
Basically, the code is meant to get 3 data values, if only the first bit of data is present, it runs x query, if first and second are present it runs y query, and so on, and so on, until it runs 8 tests on the GET data. For some background info, level = a class of study level (IGCSE, IB, A-Levels), Subject is a subject (Math, English, Science), School is the name of the school.
The database structure is as followed:
'id' INT(11)
'title' VARCHAR(255)
'description' VARCHAR(1000)
'filename' VARCHAR(255)
'uploader' VARCHAR(255)
'school' VARCHAR(255)
'subject' VARCHAR(255)
'level' VARCHAR(255)
'downloads' VARCHAR(20)
'views' VARCHAR(20)
'helpful' INT(11)
'nothelpful' INT(11)
'date' DATE
And I'm running the following PHP code:
<?
/*
YYY
YNY
YNN
YYN
NNN
NYN
NNY
NYY
*/
/* DECLARE VARS */
$subject = $_GET['subject'];
$level = $_GET['lvl'];
$school = $_GET['school'];
include("connect.php");
if($subject!="" && $level!="" && $school!=""){
/* GET Notes that have x subject, y level, and z school */
$yyyq = mysql_query("SELECT * FROM noteshare_notes WHERE subject='$subject' AND level='$level' AND school='$school' ORDER BY helpful DESC LIMIT 30"); /* quote missed here */
while($row=mysql_fetch_array($yyyq)){
echo '<span id="topic">[<a href="list.php?subject='.$row['subject'].'&lvl='.$row['level'].'">'.$row['level'].' '.$row['subject'].'</a>]</span> <a href="note.php?id='.$row['id'].'">'.$row['title'].'</a> <span id="usersize"><i>[uploaded by <a href="profile.php?id='.$row['uploader'].'">'.$row['uploader'].'</a>]</i></span><br>'; }
//yyy
}
if($subject!="" && $level!="" && $school==""){
/* Get Notes from x Subject and X Level, regardless of school. */
$yynq = mysql_query("SELECT * FROM noteshare_notes WHERE subject='$subject' AND level='$level' ORDER BY helpful DESC LIMIT 30"); /* quote missed here */
while($row=mysql_fetch_array($yynq)){
echo '<span id="topic">[<a href="list.php?subject='.$row['subject'].'&lvl='.$row['level'].'">'.$row['level'].' '.$row['subject'].'</a>]</span> <a href="note.php?id='.$row['id'].'">'.$row['title'].'</a> <span id="usersize"><i>[uploaded by <a href="profile.php?id='.$row['uploader'].'">'.$row['uploader'].'</a>]</i></span><br>'; }
//yyn
}
if($subject!="" && $level=="" && $school==""){
/* Get Level before Getting Notes without School */
$ynnq = mysql_query("SELECT * FROM noteshare_notes WHERE subject='$subject' GROUP BY level");
echo "<center>";
while($row=mysql_fetch_array($ynnq)){
echo '<a href="list.php?lvl='.$row['level'].'&subject='.$row['subject'].'">'.$row['level'].'</a><br>'; }
//ynn
}
if($subject!="" && $level=="" && $school!=""){
/* Get level based on school + subject */
$ynyq = mysql_query("SELECT * FROM noteshare_notes WHERE subject='$subject' AND school='$school' GROUP BY level");
while($row=mysql_fetch_array($ynyq)){
echo '<a href="list.php?lvl='.$row['level'].'&school='.$row['school'].'&subject='.$row['subject'].'">'.$row['level'].'</a><br>'; }
//yny
}
if($subject=="" && $level=="" && $school==""){
//Error - Nothing + Nothing + Nothing = Nothing
//nnn
}
if($subject=="" && $level=="" && $school!=""){
/* Get Subject First based on School, thus redirecting to previous ynn (reverse clause)*/
$nnyq = mysql_query("SELECT * FROM noteshare_notes WHERE school='$school' GROUP BY subject");
while($row=mysql_fetch_array($nnyq)){
echo '<a href="list.php?subject='.$row['subject'].'&school='.$row['school'].'">'.$row['subject'].'</a><br>'; }
//nny
}
if($subject=="" && $level!="" && $school!=""){
/* Get Subjects based on level + school */
$nyyq = mysql_query("SELECT * FROM noteshare_notes WHERE level='$level' AND school='$school' GROUP BY subject");
while($row=mysql_fetch_array($nyyq)){
echo '<a href="list.php?subject='.$row['subject'].'&lvl='.$row['level'].'&school='.$row['school'].'">'.$row['subject'].'</a><br>'; }
//nyy
}
if($subject=="" && $level!="" && $school==""){
/* Get Subject based on level */
$nynq = mysql_query("SELECT * FROM noteshare_notes WHERE level='$level' GROUP BY subject");
while($row=mysql_fetch_array($nyyq)){
echo '<a href="list.php?subject='.$row['subject'].'&lvl='.$row['level'].'">'.$row['subject'].'</a><br>'; }
//nyn
}
?>
Apologies as it's amassed with comments and probability, lol.
It keeps returning me with the
mysql_fetch_array(): supplied argument is not a valid MySQL result resource
error, and I have no clue how to fix it, I've tried lots, and lots of things to fix, nothing works. I think it might be due to the multiple ANDs or the fact that there aren't 30 rows in the database
Would anyone know how to fix this? Any answers will be very helpful :)
Cheers!
mysql_query, plz:if( mysql_errno() ) { echo mysql_error(); }and post the output it generates.