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PHP MySQL 读取数据

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PHP MySQL 读取数据






从 MySQL 数据库读取数据





SELECT 语句用于从数据表中读取数据:






SELECT column_name(s) FROM table_name


如需学习更多关于 SQL 的知识,请访问我们的 SQL 教程





以下实例中我们从表 MyGuests 读取了 id, firstname 和 lastname 列的数据并显示在页面上:






实例 (MySQLi - 面向对象)





<?php
$servername = "localhost";
$username = "username";
$password =

"password";
$dbname =

"myDB";

// 创建连接
$conn = new mysqli($servername,

$username, $password, $dbname);
// 检测连接
if ($conn->connect_error)

{
    die("连接失败: " . $conn->connect_error);


}

$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result

= $conn->query($sql);

if ($result->num_rows > 0) {
   

// 输出每行数据
    while($row = $result->fetch_assoc())

{
        echo "<br> id: ".

$row["id"]. " - Name: ". $row["firstname"]. " " . $row["lastname"];
   

}
} else {
    echo "0 个结果";
}


$conn->close();


?>







以下实例读取了 MyGuests 表的所有记录并显示在 HTML 表格中:






实例 (PDO)





<?php
echo "<table style='border: solid 1px black;'>";


echo "<tr><th>Id</th><th>Firstname</th><th>Lastname</th><th>Email</th><th>Reg

date</th></tr>";

class TableRows extends RecursiveIteratorIterator {

    function __construct($it) {
       

parent::__construct($it, self::LEAVES_ONLY);
    }

    function current() {
       

return "<td style='width: 150px; border: 1px solid black;'>" .

parent::current(). "</td>";
    }

   

function beginChildren() {
       

echo "<tr>";
    }

    function

endChildren() {
        echo "</tr>"

. "\n";
    }
}

$servername = "localhost";


$username = "username";
$password = "password";
$dbname = "myDBPDO";



try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname",

$username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE,

PDO::ERRMODE_EXCEPTION);
    $stmt =

$conn->prepare("SELECT * FROM MyGuests");
    $stmt->execute();

    // 设置结果集为关联数组
   

$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);

   

foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as

$k=>$v) {
        echo $v;
   

}
    $dsn = null;
}
catch(PDOException

$e)
{
    echo "Error: " . $e->getMessage();


}
$conn = null;
echo "</table>";
?>





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