I need to export data from MySQL to CSV but from specific ID. Table contains ID, ParentID and Name and here is code which exports all records:
    <?php
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "databasename";
    // Create connection
    $conn = new mysqli($servername, $username, $password, $dbname);
    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    } 
    $index = array();
    $num = 0;
    $sql = "SELECT NAME, ID, PARENTID from tablename";
    $result = $conn->query($sql);
    while($row = $result->fetch_array(MYSQLI_ASSOC)){
      $rows[] = $row;
      $index[$row['ID']] = $row;  
    }
    $output = fopen("php://output",'w') or die("Can't open php://output");
    header("Content-Type:application/csv"); 
    fputcsv($output, array('ID','NAME','PARENTID'));
    // build the tree
    foreach($index as $id => &$row){
      if ($id === 0) continue;
      $parent = $row['PARENTID'];
      $index[$parent][] = &$row;
      fputcsv($output, $row);
    }
    fclose($output) or die("Can't close php://output");
    unset($row);
    // start from this ID
    $index = $index[2];
    /* free result set */
    $result->close();
    /* close connection */
    $conn->close();
If I have this in my table (this is table declaration):
ID  PARENT    NAME
1     0       John Doe
2     1       Sally Smith
3     2       Mike Jones
4     3       Jason Williams
5     4       Sara Johnson
6     1       Dave Wilson
7     2       Amy Martin
How to export all children's for member with parentID = 2 (recursive)? With other words, I need output like this:
  ID  PARENT    NAME
  3   2         Mike Jones
  4   3         Jason Williams
  5   4         Sara Johnson
  7   2         Amy Martin
That means, exported need to be 2 members with ParentID = 2 but member Mike Jones have child (Jason Williams) which also need to be exported. Mike Williams have also one child (Sara Johnson) which also need to be exported. With other words, function need to find all members with ParentID = 2 but also they childrens and export them all. Thank you for your help.