if语句执行错误的部分

Question

When I delete a record from table, I have 8 columns in the table and if more than 8 is entered it must be showed that nothing was deleted. However every number that I give, I get the same response "deleted successfully". This is my code:

 $query = "DELETE FROM `order` WHERE orderId = '$_POST[id]'" ;
 $result = mysql_query($query);
 if(! $result )
 {
   echo ("$_POST[id] not deleted !<a href='deleteorder.php'>Back</a>"); 
 }
 else
 {
    echo ("$_POST[id] deleted succesfully! <a href='deleteorder.php'>Back</a>");
 }

Answer 1

$result will be a valid result, even when your query won't affect any rows. Use mysql_affected_rows() to check if you deleted anything.

$result = mysql_query($query);
if( mysql_affected_rows() == 0 )
{
  echo ("$_POST[id] not deleted !<a href='deleteorder.php'>Back</a>"); 
}
else
{
   echo ("$_POST[id] deleted succesfully! <a href='deleteorder.php'>Back</a>");
}

side note: the mysql_* functions are deprecated. Don't use them to write new code, especially when you are learning. Use mysqli_*or PDO instead.