Simple mysql help

[nickk]

Hi, I'm making a script that goes through a very long loop (+- 30 000 loops) and in each loop it makes a mysql query. First question, is this too much of a strain on the mysql/apache server? Second question, and most important, the script selects from a table, and if the number of rows is 0 (so it does not return anything) it does something. I'm not sure if this is the correct way to do this, but is the following correct? :

	$sql = "select * from ad where sitetitle='$title' and ad_username='$email'";
		$result = mysql_query($sql);
		if(!$rows = mysql_num_rows($result))
		{
			echo $title . "<br>";
		}

But I get errors sometimes, something along the lines of "mysql_num_rows is not a valid mysql statement" (or something like that)

[paulnaj]

Hi Nick,

You need to test the result from mysql_query() first ...

<?php 
$sql = "select * from ad where sitetitle='".$title."' and ad_username='".$email."'"; 

if(!$result = @mysql_query($sql)){
	die('mysql_query() failed ['.$sql.']');
}
$rows = mysql_num_rows($result);
if($rows == 0){ 
	echo $title . "<br>"; 
}
?>

If it dies ($result == FALSE), it'll probably be to do with the sql somehow ... maybe $title or $email are empty

Paul.