$query = mysql_query("SELECT Provider.provider_id, provider.company_name FROM Provider");

while($row = mysql_fetch_array($query)){
    echo "'".$row['provider_id']."':'".$row['company_name']."',";

}

$query = ...;
$out = Array();
while($row = mysql_fetch_assoc($query)) {
    $out[] = "'".$row['provider_id']."':'".$row['company_name']."'";
}
echo implode(",",$out);

$query = ...;
$out = Array();
while($row = mysql_fetch_assoc($query)) {
    $out[$row['provider_id']] = $row['company_name'];
}
echo json_encode($out);

$parts = array();
while($row = mysql_fetch_array($query)){
    $parts[] =  "'".$row['provider_id']."':'".$row['company_name']."'";

}

echo implode(',', $parts);

$data = array();
while($row = mysql_fetch_array($query)){
    $data[$row['provider_id']] = $row['company_name'];

}

echo json_encode($data);

$query = mysql_query("SELECT Provider.provider_id, provider.company_name FROM Provider");
$result = "";
while($row = mysql_fetch_array($query)){
    $result .= "'".$row['provider_id']."':'".$row['company_name']."',";
}
$result = rtrim($result, ',');

$query = mysql_query("SELECT Provider.provider_id, provider.company_name FROM Provider");
$result = array;
while($row = mysql_fetch_array($query)){
    $result[] = "'".$row['provider_id']."':'".$row['company_name']."',";
}
$result = implode(',' $result);