PHP, MYSQL – Query fails but no error meessage appears
Question by S.e. Estes
Back again, thanks for all the help last time. I’m running this query:
$query = "SELECT * FROM event where evLoc = ".$loc." AND evChar = ".$char;
var_dump($query);
$result = mysql_query($query, $con) or die('Error 1:'.mysql_error());
if ($result) {
$row = mysql_fetch_array($result) or die('Error 2:'.mysql_error());
var_dump(mysql_num_rows($result));
exit();
I get a message Error 2: but no mysql_error printed out. The var_dump($query) printed out a query that ran without errors in phpMyAdmin. The var_dump(mysql_num_rows($result)) did not print. Ideas?
Answer by Michael Berkowski
This is a case of being too cautious and applying error checking where it doesn’t belong.
Don’t call die() in partnership with a fetch call. The fetch intentionally returns FALSE when there are no rows available, so you don’t have an error, just no rows.
// No rows were returned, wich is FALSE
$row = mysql_fetch_array($result) or die('Error 2:'.mysql_error());
Instead, don’t call die() here:
$row = mysql_fetch_array($result);
if ($row) {
// you got something
}
Or this way:
if ($row = mysql_fetch_array($result)) {
// you got something.
}
If multiple rows are expected to be returned, fetch in a while loop.
while ($row = mysql_fetch_array($result)) {
// loops until you're out of rows
// or not at all if you have no rows
}
Answer by Starx
Apply Single Quotes in the fields of your query
$query = "SELECT * FROM event where evLoc = '".$loc."' AND evChar = '".$char."'";
You can write these in short form too. Like
$query = "SELECT * FROM event where evLoc = '$loc' AND evChar = '$char'";
Next, you might want to change your fetch portion.
while($row = mysql_fetch_assoc($result)) {
....
}
When you use this, you will avoid the error you would receive when no rows are returned.
