สอบถามการลบข้อมูลที่ซ้ำกันใน SQL ค่ะ ลบกันให้เหลือ ข้อมูลเดียวค่ะ

$dbhost = "localhost";
    $dbusername = "root";
    $dbpassword = "";
    $dbname = "url";
	
	$mysqli = new mysqli ($dbhost, $dbusername, $dbpassword, $dbname);
	
	

	$sql ="delete table 
from table tb 
left join (
  select min(no) mno, topic from table group by topic
) tbm 
on tb.topic = tbm.topic 
where tbm.mno<>tb.no";

	$query = mysqli_query($mysqli,$sql);

	if(mysqli_affected_rows($mysqli)) {
		 echo "<div style=\"font-size:30pt;\">Record delete successfully</div>";
	}

	mysqli_close($mysqli);

$sql ="delete data 
from data tb 
left join (
  select min(no) mno, topic from data group by topic
) tbm 
on tb.topic = tbm.topic 
where tbm.mno<>tb.no
";

	$mysqli->query($sql) or die ( $mysqli->error . "<br>$sql");
if($mysqli->affected_rows) {
	echo "<div style=\"font-size:30pt;\">Record delete ".$mysqli->affected_rows."</div>";
}