PHP中SQL操作affected_rows()

作用：afftected_rows()函数的作用是获取上一个执行MySQL操作所影响的行数，然后判断是否执行成功。

            适用于INSERT,UPDATE,DELETE等操作。

$conn = mysqli_connect("localhost", "username", "password", "database");
if(mysqli_connect_errno()) {
echo "数据库连接失败：" . mysqli_connect_error();
exit();
}
$query = "INSERT INTO users(name, age, email) VALUES('Alice', '25', 'alice@example.com')";
if(mysqli_query($conn, $query)) {
$affected_rows = mysqli_affected_rows($conn);
echo "插入了 " . $affected_rows . " 行数据。";
} else {
echo "插入数据失败：" . mysqli_error($conn);
}
mysqli_close($conn);

// 执行一条UPDATE语句
$query = "UPDATE users SET age='30' WHERE name='Alice'";
mysqli_query($conn, $query);
$affected_rows = mysqli_affected_rows($conn);
echo "更新了 " . $affected_rows . " 行数据。";
// 执行一条DELETE语句
$query = "DELETE FROM users WHERE age='30'";
mysqli_query($conn, $query);
$affected_rows = mysqli_affected_rows($conn);
echo "删除了 " . $affected_rows . " 行数据。";