Catching No Results with mysql_query

[Nexweb]

I have a simple question, which I can't seem to find the correct anwser. I am doing some query to a database to verify that the email that the user is trying to insert doesn't exist.

So I query the database and expect no result, if there is no result, I insert, else I send a message to the user. The problem that I have is: How do I verify that there is no record and don't have a warning in my browser?

Here is a piece of code :

#======================
# RUN QUERY
#======================	
function execute ($p_query,$p_debug)
{
              $this->query_result = mysql_query($p_query);
	if ((mysql_num_rows($this->query_result) < 1 ) && $p_debug == true)
	{
		echo "Error: No result were found for the query" . mysql_error();
		exit;
	}
	elseif (mysql_num_rows($this->query_result) < 1)
		return false;
	else
	                return $this->query_result;
	}

If I verify like : if($result), I was reading, in this doc : http://ca2.php.net/manual/en/function.mysql-query.php that it will only return false if the query is invalid, which in my case the query is valid, but I just don't have result.

So how do I verify that the query return no result without getting a Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource to the browser?

Thanks for the help

[Buddha443556]

Even if the query returns zero rows the result should still be an MySQL resource. Unless the query was semantically or syntaxically invalid then it returns false.

Maybe something like

function execute ($p_query,$p_debug) 
{
    if($this->query_result = mysql_query($p_query)){
            if ((mysql_num_rows($this->query_result) < 1 ) && $p_debug == true) 
            { 
                echo "Error: No result were found for the query" . mysql_error(); 
                exit; 
            } else {
                return $this->query_result; 
            }
    }
    return false;
}

[Nexweb]

Thanks for the reply, but still not working, the :

if($this->query_result = mysql_query($p_query)) is always true, since my query is valid, it contain something like : Resource id #4

Then I go into the if and still get the same error output to the browser with mysql_num_rows() error.

[Nexweb]

I tried this... hoping it would work:

function execute ($p_query,$p_debug)
{
	$this->result_num = 0;
	$this->query_result = mysql_query($p_query);
	while (mysql_fetch_array($this->query_result))
	{
		$this->result_num = 1;
		break;
	}

	if ($this->result_num == 0 && $p_debug == true)
	{
		echo "Error: No result were found for the query" . mysql_error();
		exit;
	}

	elseif ($this->result_num == 0)
		return false;

	else
		return $this->query_result;
}

But then I get Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource ...

I am starting to think that the only way to make clean verification is to put the debugger to off... which is rediculus just for a query.

Hopefully I will be able to use the "try - catch" with PHP 5 😉

[mrhappiness]

change your mysql_query to

 $this->query_result = mysql_query($p_query) or die(mysql_error()); 

what happens?

[Nexweb]

Thanks for the input. I finally got it working with the " or die " I don't really understand why... but I can handle the error better now, since the mysql_error() doesn't return anything, it just dies and sends no message.

I did have to rewrite a function to handle the insert, but at least now I have a good handling of error, here is the final code :

	#======================
	# RUN QUERY
	#======================	
	function execute ($p_query,$p_debug)
  { 
        $this->result_num = 0; 
        $this->query_result = mysql_query($p_query) or die(mysql_error()); 
        while (mysql_fetch_array($this->query_result)) 
        { 
            $this->result_num = 1; 
            break; 
        } 

    if ($this->result_num == 0 && $p_debug == true) 
    { 
        echo "Error: No result were found for the query" . mysql_error(); 
        exit; 
    } 

    elseif ($this->result_num == 0) 
        return false; 

    else 
        return $this->query_result; 
}

#======================
# RUN INSERT
#======================	
function insert ($p_query,$p_debug)
{

	$this->query_result = mysql_query($p_query) or die(mysql_error());

	return $this->query_result;
}