php mysql队列

<?php
// 数据库连接
$mysqli = new mysqli("localhost", "username", "password", "database");

if ($mysqli->connect_error) {
    die("连接失败: " . $mysqli->connect_error);
}

// 插入任务到队列
function enqueue($mysqli, $task) {
    $sql = "INSERT INTO queue (task) VALUES (?)";
    $stmt = $mysqli->prepare($sql);
    $stmt->bind_param("s", $task);
    $stmt->execute();
}

// 从队列中取出任务并处理
function dequeue($mysqli) {
    $sql = "SELECT task FROM queue ORDER BY id ASC LIMIT 1 FOR UPDATE SKIP LOCKED";
    $result = $mysqli->query($sql);
    if ($result->num_rows > 0) {
        $row = $result->fetch_assoc();
        $task = $row['task'];
        $delete_sql = "DELETE FROM queue WHERE task = ?";
        $delete_stmt = $mysqli->prepare($delete_sql);
        $delete_stmt->bind_param("s", $task);
        $delete_stmt->execute();
        return $task;
    }
    return null;
}

// 示例任务
$task = "发送电子邮件";
enqueue($mysqli, $task);

// 处理任务
while ($task = dequeue($mysqli)) {
    echo "处理任务: " . $task . "\n";
    // 这里可以添加具体的任务处理逻辑
}

$mysqli->close();
?>