<?php
$con=mysqli_connect("localhost","username","password","database");
// 检测连接
if (mysqli_connect_errno())
{
    echo "连接失败: " . mysqli_connect_error();
}

$result = mysqli_query($con,"SELECT * FROM Persons ORDER BY age");

while($row = mysqli_fetch_array($result))
{
    echo $row['FirstName'];
    echo " " . $row['LastName'];
    echo " " . $row['Age'];
    echo "<br>";
}

mysqli_close($con);
?>
<?php
$con=mysqli_connect("localhost","username","password","database");
// 检测连接
if (mysqli_connect_errno())
{
    echo "连接失败: " . mysqli_connect_error();
}

$result = mysqli_query($con,"SELECT * FROM Persons
WHERE FirstName='Peter'");

while($row = mysqli_fetch_array($result))
{
    echo $row['FirstName'] . " " . $row['LastName'];
    echo "<br>";
}
?>
<?php
$con=mysqli_connect("localhost","username","password","database");
// 检测连接
if (mysqli_connect_errno())
{
    echo "连接失败: " . mysqli_connect_error();
}

mysqli_query($con,"UPDATE Persons SET Age=36
WHERE FirstName='Peter' AND LastName='Griffin'");

mysqli_close($con);
?>
<?php
$con=mysqli_connect("localhost","username","password","database");
// 检测连接
if (mysqli_connect_errno())
{
    echo "连接失败: " . mysqli_connect_error();
}

mysqli_query($con,"DELETE FROM Persons WHERE LastName='Griffin'");

mysqli_close($con);
?>