$query='insert into p1(info) values(?)';
$query2='select info from p1 where id=?';
$country=2;

// 创建预处理语句
$stmt=mysqli_stmt_init($link);

if (mysqli_stmt_prepare($stmt,$query2))
{
    
    // 绑定参数
    mysqli_stmt_bind_param($stmt,"i",$country);
    
    // 执行查询
    mysqli_stmt_execute($stmt);
    
    // 绑定结果变量
   mysqli_stmt_bind_result($stmt,$name); //此处的变量有几个查询参数就返回写几个
    
    // 获取值
    mysqli_stmt_fetch($stmt); 
    
     printf("国家的网站为：%s",$name);
    
    // 关闭预处理语句
    mysqli_stmt_close($stmt);
}

$query2='select id,info from p1 where id=? or id=?';
$country=2;
$country2=10;
// 创建预处理语句
$stmt=mysqli_stmt_init($link);

if (mysqli_stmt_prepare($stmt,$query2))
{
    
    // 绑定参数
    mysqli_stmt_bind_param($stmt,"ii",$country,$country2);
    
    // 执行查询
    mysqli_stmt_execute($stmt);
    //暑促一个对行数的影响
    var_dump(mysqli_affected_rows($link)) ;
    // 绑定结果变量
    mysqli_stmt_bind_result($stmt,$id,$name);
    
    // 获取值
 

    while(mysqli_stmt_fetch($stmt)){
        printf("查询结果：%s,%s",$id,$name);
}

$query='insert into p1(info) values(?)';
$country=2;

// 创建预处理语句
$stmt=mysqli_stmt_init($link);
// 绑定参数
if (mysqli_stmt_prepare($stmt,$query))
{
    
    // 绑定参数
    mysqli_stmt_bind_param($stmt,"s",$country);
    
    
    // 关闭预处理语句
    mysqli_stmt_close($stmt);
}

    //从一个prepared语句返回结果集元数据，配合相关函数，可以用来获得字段的相关信息==================
    var_dump($a=mysqli_stmt_result_metadata ($stmt ));
    //获取字段信息
    var_dump(mysqli_fetch_field($a));
    var_dump(mysqli_fetch_field($a));