mySQL SELECT matches empty fields, not sure why?

[ArmyofHarmony]

Hi guys

I have another fairly simple question (I guess!).

Basically I've written this statement in PHP:

$finduserid="SELECT player_id from Player WHERE username = '$username'";
$player_id = mysql_query($finduserid);

while( $row = mysql_fetch_array($player_id))
{

echo ($row['player_id'] . "<br />");


}


The problem is I have some username rows in my mySQL table that are blank.

When I loop through and echo out all the player_ids that are found (which should only be one), the query lists all the blank fields too.

Why is mySQL matching against blank fields, if I've specified a username for it to look for in the table?

Many thanks

 

[ArmyofHarmony]

Thanks for the advice. IT turns out a blank variable was being passed through, causing blank values to be found in the database.

Doh!