PHP mysqli field_count() 函数
示例 - 面向对象的样式
假设我们有一个 "Friends" 表，其中有 3 个字段 20 行记录。返回最近查询的列数：
<?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();
}
$mysqli -> query("SELECT * FROM Friends");
// Get number of columns - will return 3
$mysqli -> field_count();
$mysqli -> close();
?>
$mysqli = new mysqli("localhost","my_user","my_password","my_db");
if ($mysqli -> connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
exit();
}
$mysqli -> query("SELECT * FROM Friends");
// Get number of columns - will return 3
$mysqli -> field_count();
$mysqli -> close();
?>
查看底部的程序样式示例。
定义和用法
field_count() / mysqli_field_count() 函数返回最近查询的列数。
语法
面向对象的风格：
$mysqli -> field_count()
程序风格：
mysqli_field_count(connection)
参数值
| 参数 | 描述 |
|---|---|
| connection | 必需。规定要使用的 MySQL 连接。 |
技术细节
| 返回值: | 返回一个表示结果集中列数的整数。 |
|---|---|
| PHP 版本: | 5+ |
示例 - 程序样式
假设我们有一个 "Friends" 表，其中有 3 个字段 20 行记录。返回最近查询的列数：
<?php
$con = mysqli_connect("localhost","my_user","my_password","my_db");
if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit();
}
mysqli_query($con, "SELECT * FROM Friends");
// Get number of columns - will return 3
mysqli_field_count($con);
mysqli_close($con);
?>
$con = mysqli_connect("localhost","my_user","my_password","my_db");
if (mysqli_connect_errno()) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
exit();
}
mysqli_query($con, "SELECT * FROM Friends");
// Get number of columns - will return 3
mysqli_field_count($con);
mysqli_close($con);
?>
