不包含查询值的数组

I am trying to get an array to contain two values; SkillID and Description. However when I print the value of the array it is only showing Description. How can I get an array to show both??

$skillresult = $con->query("SELECT userskills.`SkillID`, `Description`, `Experience` FROM `User` INNER JOIN `userskills` ON User.`UserId` = userskills.`UserId` LEFT OUTER JOIN `Skills` ON userskills.`SkillID` = Skills.`SkillID` WHERE user.`UserID` ='$User'") 
    or die(mysqli_error($con));

    $skills_array = array();

    while($r=mysqli_fetch_array($skillresult))
    {
    if (!isset($skills_array[$r['SkillID']]))
    {
        $skills_array[$r['SkillID']] = array();
    }
    $skills_array[$r['SkillID']][] = $r['Description'];
}

Print Output:

Array ( [0] => Array ( [0] => Java ) [1] => Array ( [0] => Unix ) )

Description 'Java' should have the SkillID of '1' and Unix '6'.

Is the $skills_array array really supposed to be 2-dimensional?
Isn't this what you really want?

Array ( 1 => Java, 6 => Unix)

In which case, this could work:

while($r=mysqli_fetch_array($skillresult))
{
    $skills_array[$r['SkillID']] = $r['Description'];
}