问PHP中的动态Optgroup

EN

$result = mysqli_query($conn, "SELECT * FROM Members ORDER BY GroupName");
$groupName = '';
$first = true;
echo '<select>';
while ($row = mysqli_fetch_assoc($result)){
    if ($row['GroupName'] != $groupName) {
        $groupName = $row['GroupName']; // Just set the new group name
        if (!$first) { // Add a closing tag when we change the group, but only if we're not in the first loop
            echo '</optgroup>';
        } else {
            $first = false; // Make sure we don't close the tag first time, but do after the first loop
        }
        echo '<optgroup label="' . $groupName . '">';
    }
    // We want to echo the options every loop so it's outside the if condition
    echo '<option value="' . $row['MemberName'] . '">' . $row['ValueName'] . '</option>';
}
echo '</select>';

// query to get all records from database table
$result = mysqli_query($conn, "SELECT distinct MemberName,GroupName,ValueName from Members order by MemberName ASC");
while ($row = mysqli_fetch_assoc($result)){
    // generate an array with keys as group name
    $array[$row['GroupName']][] = $row;
}

// loop the array to create optgroup
foreach($array as $key=>$value){
    // check if its an array
    if(is_array($value)){
        // create optgroup for each groupname
        echo "<optgroup class='".$key."'>";
        foreach($value as $k=>$v){
            echo "<option value='".$v['membername']."'>'".$v['membername']."'</option>";
        }
        echo "</optgroup>";
    }
}