## MySQLi - 面向对象 ### 查询数据 ```php $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 results"; } ``` ### 条件查询 ```php $result = mysqli_query($con,"SELECT * FROM Persons WHERE FirstName='Peter'"); while($row = mysqli_fetch_array($result)) { echo $row['FirstName'] . " " . $row['LastName']; echo "<br>"; } ``` ## PDO ```php try { $stmt = $conn->prepare("SELECT * FROM MyGuests"); $stmt->execute(); // 设置结果集为关联数组 $result = $stmt->setFetchMode(PDO::FETCH_ASSOC); } catch(PDOException $e) { echo "Error: " . $e->getMessage(); } ```