PHP MySQL 讀取數(shù)據(jù)

當(dāng) PHP 連接到 MySQL 數(shù)據(jù)庫后，需要向數(shù)據(jù)庫讀取數(shù)據(jù)？那么怎么讀取呢？一起來看看。

從 MySQL 數(shù)據(jù)庫讀取數(shù)據(jù)

SELECT 語句用于從數(shù)據(jù)表中讀取數(shù)據(jù):SELECT column_name(s) FROM table_name

我們可以使用 * 號來讀取所有數(shù)據(jù)表中的字段：SELECT * FROM table_name

如需學(xué)習(xí)更多關(guān)于 SQL 的知識(shí)，請?jiān)L問我們的 SQL 教程。

以下實(shí)例中我們從表 MyGuests 讀取了 id, firstname 和 lastname 列的數(shù)據(jù)并顯示在頁面上：

實(shí)例 (MySQLi - 面向?qū)ο?

$servername = "localhost";

$username = "username";

$password = "password";

$dbname = "myDB";

// 創(chuàng)建連接

$conn = mysqli_connect($servername, $username, $password, $dbname);

// 檢測連接

if ($conn->connect_error) {

die("Connection failed: " . $conn->connect_error);

}

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

$result = $conn->query($sql);

if ($result->num_rows > 0) {

// 輸出每行數(shù)據(jù)

while($row = $result->fetch_assoc()) {

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

}

} else {

echo "0 results";

}

mysqli_close(%conn);

?>

以下實(shí)例讀取了 MyGuests 表的所有記錄并顯示在 HTML 表格中：

實(shí)例 (PDO)

echo "

echo "

IdFirstnameLastnameEmailReg date";

class TableRows extends RecursiveIteratorIterator {

function __construct($it) {

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

}

function current() {

return "

" . parent::current(). "";

}

function beginChildren() {

echo "

";

}

function endChildren() {

echo "

" . "\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(shè)置結(jié)果集為關(guān)聯(lián)數(shù)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 "

";

?>

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