php array_unique与array_filter结合使用，输出不正确

In a database table are multiple entries related to a customer. Each entry will have time_1, time_2, time_3, time_4, time_5 and time_6 fields. I have looped through the entries and used this to combine these times to create a round cycle for a day:

while($row=mysql_fetch_assoc($script_check))
        {
            $prerounds = array_filter($row);
            $rounds = array_unique(array_merge($prerounds));    
        }

This works however if one entry has times 1-4 set and the second entry has times 1-3 set the fourth time will be totally removed thus only times 1-3 are put into the array. How can I combine these fields without losing data when some are blank? This strategy so far has been to strip the $row of all blanks then merge it together to create one set of round times related to that customer for that day. Thanks.

As the OP requested:

Basically, your main problem is you're re-initializing $rounds on each iteration, you're not merging any existing array with a new one.

$rounds = array();
while($row = $pdo->fetch(PDO::FETCH_ASSOC))
{
    $rounds = array_merge($rounds, array_unique(array_filter($row)));
}

Hmz... apart from mysql_* being deprecated (that's why I used PDO in my snippet), you should really check your logic... perhaps a decent query might be more suitable, or a simple set of if's. It's even likely to be faster that way