PHP lengths / mysqli_fetch_lengths() 函数

示例 - 面向对象风格

返回结果集中当前行的字段长度：

<?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 * FROM Persons ORDER BY Lastname";

if ($result = $mysqli -> query($sql)) {
$row = $result -> fetch_row();
// Display field lengths
foreach ($result -> lengths as $i => $val) {
printf("Field %2d has length: %2d\n", $i + 1, $val);
}
$result -> free_result();
}

$mysqli -> close();
?>

查看底部的程序样式示例。

定义和用法

lengths / mysqli_fetch_lengths() 函数返回结果集中当前行的字段长度。

语法

面向对象风格：

$mysqli_result -> lengths

程序风格：

mysqli_fetch_lengths( result)

参数值

Parameter	Description
result	Required. Specifies a result set identifier returned by mysqli_query(), mysqli_store_result() or mysqli_use_result()

技术细节

返回值：	返回一个整数数组，表示每个字段（列）的大小。如果发生错误则为 FALSE
PHP 版本：	5+

示例 - 程序风格

返回结果集中当前行的字段长度：

<?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 * FROM Persons ORDER BY Lastname";

if ($result = mysqli_query($con, $sql)) {
$row = mysqli_fetch_row($result);
// Display field lengths
foreach (mysqli_fetch_lengths($result) as $i => $val) {
printf("Field %2d has length: %2d\n", $i+1, $val);
}

mysqli_free_result($result);
}

mysqli_close($con);
?>

❮ PHP MySQLi 参考