PHP MySQL 讀取數據

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從 MySQL 數據庫讀取數據

SELECT 語句用於從數據表中讀取數據:

SELECT column_name(s) FROM table_name

如需學習更多關於 SQL 的知識，請訪問我們的 SQL 教程。

以下實例中我們從表 MyGuests 讀取了 id, firstname 和 lastname 列的數據並顯示在頁面上：

實例 (MySQLi - 面向對象)

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

// 創建連接
$conn = new mysqli($servername, $username, $password, $dbname);
// 檢測連接
if ($conn->connect_error) {
    die("連接失敗: " . $conn->connect_error);
}

$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 輸出每行數據
    while($row = $result->fetch_assoc()) {
        echo "<br> id: ". $row["id"]. " - Name: ". $row["firstname"]. " " . $row["lastname"];
    }
} else {
    echo "0 個結果";
}
$conn->close();
?>

以下實例讀取了 MyGuests 表的所有記錄並顯示在 HTML 表格中：

實例 (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();

    // 設置結果集為關聯數組
    $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>";
?>