why this mysql query is not working? - php

Question

Please help me regarding the specified problem:
The code section:
$result = mysql_query("SELECT *, UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate FROM events ORDER BY eventdate where
id='$_GET[id];'");
// the above query is not working
if ( mysql_num_rows($result) == 0 ) {
print "<p>No events right now.</p>\n";
}
else {
$lasteventmonth = '';
while ($row = mysql_fetch_array($result)) {
$eventmonth="";
$eventmonth = date("F Y",$row['eventdate']);
if ($lasteventmonth != $eventmonth) {
print "<p style='font-size: 18px;'><b>$eventmonth</b></p>";
}
$lasteventmonth = $eventmonth;
showEvent($row);
}
}
?>
........................
........................//other codes
when the code evaluates as follows:
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in C:\Users\Fagun\Desktop\UsbWebserver\Root\mapcal\mapcal.php on line 122
No events right now.++++++++

Answer 1

After your call to mysql_query, use this:
if (! $result) {
echo mysql_errno() . ": " . mysql_error(). "\n";
}
this will tell you exactly, why MySQL won't run your query.

Answer 2

is ID a String or int? Either way I guess you shouldn't include a trailing semicolon?
Try changing it as follows...
$result = mysql_query("SELECT *, UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate FROM events ORDER BY eventdate where
id='$_GET[id]'");

Answer 3

I assume it's an issue with how you're using building the query and concatenating the id. Try this instead (notice how the ID is concatenated):
$query = "SELECT *, UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate FROM events
ORDER BY eventdate where
id='".$_GET[id]."'";
$result = mysql_query($query) or die(mysql_error());
You don't have to break it into 2 pieces, but - this should be easier to read and understand. You can even echo out the query before running it to see what query is actually being created, and try it manually on your database.
The or die(mysql_error()) part will give you specifics on what the issue is (if it wasn't the ID issue).

Answer 4

Quote values properly :
$_GET[id] should be $_GET['id']
Try below:
$result = mysql_query("SELECT *, UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate FROM events ORDER BY eventdate where
id='".$_GET['id']."');

Answer 5

Try this:
"SELECT *, UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate FROM events ORDER BY eventdate where
id='".$_GET['id'].";'"
I'm assuming that id does not come from user input. If it does, this is vulnerable to a SQL injection attack.

Answer 6

try:
$result = mysql_query("SELECT *,
UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate
FROM events
ORDER BY eventdate
where id= '" . intval($_GET['id']) . "'");
if($result)
{
//Do code
}
use intval() to make sure $_GET['id'] is an integer.
use the if statement to make sure the query has executed correctly.

Answer 7

Try this
$result = mysql_query("SELECT *, UNIX_TIMESTAMP(eventdate) AS eventdate,
UNIX_TIMESTAMP(throughdate) AS throughdate FROM events where
id='".$_GET['id']."' ORDER BY eventdate");