อยากจะ count column ครับ ทำได้ไหมครับ PHP + MYSQL ครับ

<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
    echo 'Could not run query: ' . mysql_error();
    exit;
}

/* returns 2 because id,email === two fields */
echo mysql_num_fields($result);
?>

<?php

$result = mysql_query("SELECT * FROM table_a");

while($row=mysql_fetch_array($result)) {

If(!empty($row['field1'])&&!empty($row['field2'])&&!empty($row['field3'])&&!empty($row['chk_field1'])&&!empty($row['chk_field2'])&&!empty($row['chk_field3'])) {
$up_status = "Y";
} else {
$up_status = "N";
}

mysql_query("UPDATE table_a SET status='".$up_status."' WHERE id='".$row['id']."'");

}

?>