PHP mysqli fetch_fields() 函数

定义和用法

fetch_fields() / mysqli_fetch_fields() 函数返回一个对象数组，这些对象表示结果集中的字段。

实例

例子 1 - 面向对象风格

返回一个对象数组，这些对象表示结果集中的字段，然后打印每个字段的名称、表和最大长度：

<?php
$mysqli = new mysqli("localhost","my_user","my_password","my_db");

if ($mysqli -> connect_errno) {
  echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
  exit();
}

$sql = "SELECT Lastname, Age FROM Persons ORDER BY Lastname";

if ($result = $mysqli -> query($sql)) {

  // 获取所有字段的字段信息
  $fieldinfo = $result -> fetch_fields();

  foreach ($fieldinfo as $val) {
    printf("Name: %s\n", $val -> name);
    printf("Table: %s\n", $val -> table);
    printf("Max. Len: %d\n", $val -> max_length);
  }
  $result -> free_result();
}

$mysqli -> close();
?>

例子 2 - 过程式风格

返回一个对象数组，这些对象表示结果集中的字段，然后打印每个字段的名称、表和最大长度：

<?php
$con = mysqli_connect("localhost","my_user","my_password","my_db");

if (mysqli_connect_errno()) {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  exit();
}

$sql = "SELECT Lastname, Age FROM Persons ORDER BY Lastname";

if ($result = mysqli_query($con , $sql)) {

  // 获取所有字段的字段信息
  $fieldinfo = mysqli_fetch_fields($result);

  foreach ($fieldinfo as $val) {
    printf("Name: %s\n", $val->name);
    printf("Table: %s\n", $val->table);
    printf("Max. Len: %d\n", $val->max_length);
  }
  mysqli_free_result($result);
}

mysqli_close($con);
?>

语法

面向对象风格：

$mysqli_result -> fetch_fields()

过程式风格：

mysqli_fetch_fields(result)

技术细节