How to remove duplicate values in assoc array

Question

I have an associate array. I want to remove duplicate values if the value has appear first. Let's say if DC-30 has appear first, remove all DC-30 in the associate array. If HSD-M has appeared already, remove all HSD-M in the associate array. I'm doing all of this in while($row = mysql_fetch_assoc($result)) if that makes any difference. Any help here?

string(5) "DC-30" 
string(5) "DC-30" 
string(10) "GigaDigHD2" 
string(11) "Turbo-Frame" 
string(5) "HSD-M" 
string(5) "HSD-M" 
string(5) "HSD-M" 
string(5) "HSD-M"

EDIT: These array values are not hard coded. They are from a table in the database, that's why I want to remove duplicated values.

Wanted output is:

string(5)  "DC-30" 
string(10) "GigaDigHD2" 
string(11) "Turbo-Frame" 
string(5)  "HSD-M"

2nd EDIT:

while($row = mysql_fetch_assoc($result))
{
    $tester_name = $row['tester_name'];
    $board_name = $row['board_name'];
    $config = $row['config'];
    $req_config = $row['configuration'];

    echo $bomb = array_unique($board_name, SORT_REGULAR); //Edited here

    $ex_req_config = explode(",", $req_config);
    $count_req_config =  count($ex_req_config);

    $match = 0;

    foreach($ex_req_config as $value)
    {
        $number = strlen($value);
        $arr = str_split($value, $number);

        if(in_array($config, $arr))
        {
            $match += 1;
            $match /= ($count_req_config / 100);
        }
    }

    /*  echo "<tr class = \"thisRow\">
                <td></td>
                <td></td>
                <td class = \"match\">$match%</td>
             </tr>";*/
}

Answer 1

If a grouping inside the query itself is not an option, initialise an array before the loop starts and manage it inside the loop:

$boards = [];

while ($row = mysql_fetch_assoc($result)) {
    // ...
    $boards[$board_name] = $board_name;
}

At the end of the loop $boards will be an array with all the unique values.