在PHP中,你可以使用原生的MySQL扩展(mysql
)、MySQLi扩展(mysqli
)或PDO(PHP Data Objects)来查询MySQL数据库。由于mysql
扩展已经在PHP 5.5.0中被弃用,并在PHP 7.0.0中被移除,因此建议使用mysqli
或PDO。
以下是使用mysqli
和PDO进行原生查询的示例:
<?php
// 数据库连接信息
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "myDB";
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// 检查连接
if ($conn->connect_error) {
die("连接失败: " . $conn->connect_error);
}
// 执行查询
$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// 输出数据
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
}
} else {
echo "0 结果";
}
// 关闭连接
$conn->close();
?>
<?php
// 数据库连接信息
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "myDB";
try {
// 创建连接
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// 设置PDO错误模式为异常
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// 执行查询
$sql = "SELECT id, name, email FROM users";
$stmt = $conn->query($sql);
// 设置结果集为关联数组
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
// 输出数据
foreach($stmt->fetchAll() as $row) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
}
} catch(PDOException $e) {
echo "错误: " . $e->getMessage();
}
// 关闭连接
$conn = null;
?>
<?php
// 数据库连接信息
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "myDB";
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// 检查连接
if ($conn->connect_error) {
die("连接失败: " . $conn->connect_error);
}
// 准备预处理语句
$stmt = $conn->prepare("SELECT id, name, email FROM users WHERE id = ?");
$stmt->bind_param("i", $id);
// 设置参数并执行
$id = 1;
$stmt->execute();
// 绑定结果变量
$stmt->bind_result($id, $name, $email);
// 获取结果
while ($stmt->fetch()) {
echo "id: " . $id . " - Name: " . $name . " - Email: " . $email . "<br>";
}
// 关闭语句和连接
$stmt->close();
$conn->close();
?>
<?php
// 数据库连接信息
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "myDB";
try {
// 创建连接
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// 设置PDO错误模式为异常
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
// 准备预处理语句
$stmt = $conn->prepare("SELECT id, name, email FROM users WHERE id = :id");
$stmt->bindParam(':id', $id);
// 设置参数并执行
$id = 1;
$stmt->execute();
// 设置结果集为关联数组
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
// 输出数据
foreach($stmt->fetchAll() as $row) {
echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
}
} catch(PDOException $e) {
echo "错误: " . $e->getMessage();
}
// 关闭连接
$conn = null;
?>