如何从PHP创建MySQL存储过程？

<?php
// 1. 创建一个MySQL数据库连接
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database_name";

$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 2. 编写SQL语句以创建存储过程
$sql = "CREATE PROCEDURE GetSum(IN num1 INT, IN num2 INT, OUT sum INT)
        BEGIN
            SET sum = num1 + num2;
        END";

// 3. 使用PHP执行SQL语句
if ($conn->query($sql) === TRUE) {
    echo "存储过程创建成功";
} else {
    echo "创建失败: " . $conn->error;
}

// 4. 关闭数据库连接
$conn->close();
?>

CALL GetSum(10, 20, @sum);
SELECT @sum;

<?php
// 1. 创建一个MySQL数据库连接
$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database_name";

$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 2. 调用存储过程
$sql = "CALL GetSum(10, 20, @sum)";
$result = $conn->query($sql);

// 3. 获取存储过程的输出参数
$sql = "SELECT @sum";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "和为: " . $row["@sum"];
    }
} else {
    echo "0 结果";
}

// 4. 关闭数据库连接
$conn->close();
?>