PHP从MySQL导出到CSV

我需要将数据从MySQL导出到CSV,但要从特定ID导出.该表包含ID,ParentID和Name,这是导出所有记录的代码：

    <?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();

如果我在表中有此表(这是表声明)：

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

如何导出parentID = 2(递归)的成员的所有子代？
换句话说,我需要这样的输出：

  ID  PARENT    NAME
  3   2         Mike Jones
  4   3         Jason Williams
  5   4         Sara Johnson
  7   2         Amy Martin

这意味着,导出的必须是ParentID = 2的2个成员,但是成员Mike Jones的孩子(Jason Williams)也需要导出.迈克·威廉姆斯还有一个孩子(萨拉·约翰逊),也需要出口.换句话说,函数需要查找ParentID = 2的所有成员,但也要找到所有成员并将其全部导出.谢谢您的帮助.

解决方法:

$sql = "SELECT NAME, ID, PARENTID from tablename WHERE ID=2";

标签：export-to-csv,php,mysqli
来源： https://codeday.me/bug/20191013/1907871.html