php - 函数返回最新成员的值

Question

我正在尝试使用以下示例创建我的第一个函数:

function getNumMembers(){

    if($this->num_members < 0) {
        $q = "SELECT * FROM ".TBL_USERS;
        $result = mysql_query($q, $this->connection);
        $this->num_members = mysql_numrows($result);
    }

    return $this->num_members;
}

现在我想从数据库中获取最新的成员并创建这个:

function getNewestMember(){
    $q = "SELECT LAST(username) FROM ".TBL_USERS;
    $result = mysql_query($q, $this->connection);
}

但是因为这只是最新用户名的结果，我不知道应该如何显示这一点，有什么建议吗？

Answer 1

如果您有任何主键或 Unique key或Candidate key以及ID

使用此查询

$q = "SELECT * FROM ".TBL_USERS." ORDER BY ID DESC LIMIT 1;

或者另一个选项是您可以将 create_date 存储为时间戳

Alter table ".TBL_USERS." add created_date TIMESTAMP DEFAULT CURRENT_TIMESTAMP
SELECT * FROM ".TBL_USERS." ORDER BY created_date DESC LIMIT 1

现在可以通过以下方式显示 Lastest_username:

function getNewestMember(){
    $q = "SELECT user_name FROM ".TBL_USERS." ORDER BY created_date DESC LIMIT 1";
    $result = mysql_query($q, $this->connection) or die(mysql_error());
    $row = mysql_fetch_array($result);
    return $row['user_name'];
}
//calling now function
echo($this->getNewestMember());//if i working with objects
echo(getNewestMember());//if i working normally

Note: Mysql is officially deprecated as of PHP v5.5.0 use mysqli or pdo for prevent from sql Injection also.