mysql_num_rows() expects parameter 1 to be resource, string given in

Question

I have read through many other threads about this exact problem, but i for some reason can not solve my problem. Really need some help.

if (!$username||!$passwo         


        

Answer 1

Ok, if anyone having the same issue, just add the variable within the if() statement two times, like so:

$Query = mysql_query($sql); 
IF($Query && mysql_num_rows($Query)> 0){ // continue with the code}

This should fix the issue.

Answer 2

First You make sure that connection established correctly to the database.

Instead of writing query directly in

$check = mysql_query("SELECT * FROM Test WHERE username = '$username'");

Store the query in variable as

$query = "SELECT * FROM Test WHERE username = '".$username."'";

and execute it as

$check = mysql_query($query);

if you are still facing the issue,

echo the query as

echo $query;

and execute the query directly in phpmyadmin and you can find the issue.

I hope this helps.

Answer 3

Try to like this:

$query = "SELECT username FROM $this->table WHERE username='$sUser'";
$result = mysql_query($query);  
$num_rows = mysql_num_rows($result); 

Answer 4

You can try like this

$sql= "SELECT * FROM Test WHERE username = '".$username."'";
$check = mysql_query($sql);

I think your $check returns null that is no user with this username and null can't be a parameter mysql_num_rows() function.

if($check)
{
    echo "Username already taken";
}
else
{
  echo "Username available";
  // do other actions
}

Answer 5

Change:

$check = mysql_query("SELECT * FROM Test WHERE username = '$username'");

to

$check = mysql_query("SELECT * FROM Test WHERE username = '$username'") or die(mysql_error());

And you will see any potential errors that happens in the query.

Also, I would highly recomend using either PDO or Mysqli instead of mysql functions, as they are deprecated and will be removed in future php versions.