建構銷售預測功能的企業資源計畫（ERP）系統的PHP開發

CREATE TABLE sales (
    id INT PRIMARY KEY AUTO_INCREMENT,
    date DATE,
    sales_amount DECIMAL(10, 2)
);

// 查询数据库中的销售数据
$query = "SELECT * FROM sales";
$result = mysqli_query($conn, $query);

// 清洗处理数据
while ($row = mysqli_fetch_assoc($result)) {
    $date = $row['date'];
    $salesAmount = $row['sales_amount'];

    // 处理异常值
    if ($salesAmount < 0 || $salesAmount > 1000000) {
        continue; // 跳过异常值
    }

    // 处理缺失值
    if (empty($salesAmount)) {
        $salesAmount = 0;
    }
    
    // 存储处理后的数据
    $query = "INSERT INTO cleaned_sales (date, sales_amount) VALUES ('$date', $salesAmount)";
    mysqli_query($conn, $query);
}

// 查询数据库中的清洗后的销售数据
$query = "SELECT * FROM cleaned_sales";
$result = mysqli_query($conn, $query);

// 准备数据
$x = []; // 日期
$y = []; // 销售金额

while ($row = mysqli_fetch_assoc($result)) {
    $x[] = strtotime($row['date']);
    $y[] = $row['sales_amount'];
}

// 线性回归分析
$coefficients = linear_regression($x, $y); 

// 输出结果
echo "斜率：".$coefficients['slope']."<br>";
echo "截距：".$coefficients['intercept']."<br>";

function linear_regression($x, $y) {
    $n = count($x); // 数据点个数
    $sumX = array_sum($x);
    $sumY = array_sum($y);
    $sumXY = 0;
    $sumXX = 0;

    for ($i = 0; $i < $n; ++$i) {
        $sumXY += $x[$i] * $y[$i];
        $sumXX += $x[$i] * $x[$i];
    }

    $slope = ($n * $sumXY - $sumX * $sumY) / ($n * $sumXX - $sumX * $sumX);
    $intercept = ($sumY - $slope * $sumX) / $n;

    return ['slope' => $slope, 'intercept' => $intercept];
}

// 查询数据库中的预测数据
$query = "SELECT * FROM sales_forecast";
$result = mysqli_query($conn, $query);

// 准备数据
$labels = []; // 日期
$data = []; // 预测销售金额

while ($row = mysqli_fetch_assoc($result)) {
    $labels[] = $row['date'];
    $data[] = $row['sales_amount'];
}

// 生成折线图
echo '<canvas id="salesForecastChart"></canvas>';

// 绘制折线图
echo '<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>';
echo '<script>';
echo 'var ctx = document.getElementById("salesForecastChart").getContext("2d");';
echo 'var myChart = new Chart(ctx, {';
echo '    type: "line",';
echo '    data: {';
echo '        labels: '.json_encode($labels).',';
echo '        datasets: [{';
echo '            label: "Sales Forecast",';
echo '            data: '.json_encode($data).',';
echo '            fill: false,';
echo '            backgroundColor: "rgba(75, 192, 192, 0.4)",';
echo '            borderColor: "rgba(75, 192, 192, 1)",';
echo '            borderWidth: 2';
echo '        }]';
echo '    },';
echo '    options: {';
echo '        responsive: true,';
echo '        scales: {';
echo '            y: {';
echo '                beginAtZero: true';
echo '            }';
echo '        }';
echo '    }';
echo '});';
echo '</script>';