PHP 分頁技術完整指南：原理、SQL LIMIT 與可複用分頁類

分頁核心原理

分頁需三個關鍵參數：

• $pageSize：每頁筆數
• $currentPage：當前頁碼（從 1 開始）
• $totalRows：總資料筆數

衍生參數：

• $offset = ($currentPage - 1) * $pageSize：起始位移
• $totalPages = ceil($totalRows / $pageSize)：總頁數

MySQL LIMIT 語法

簡易分頁實作（PDO 版）

query('SELECT COUNT(*) FROM articles');
    $totalRows = $stmt->fetchColumn();
    $totalPages = (int)ceil($totalRows / $pageSize);

    // 取得當頁資料
    $stmt = $pdo->prepare('SELECT * FROM articles ORDER BY id DESC LIMIT :offset, :pageSize');
    $stmt->bindValue(':offset', $offset, PDO::PARAM_INT);
    $stmt->bindValue(':pageSize', $pageSize, PDO::PARAM_INT);
    $stmt->execute();
    $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);

    return [
        'data' => $rows,
        'pagination' => [
            'current_page' => $page,
            'page_size' => $pageSize,
            'total_rows' => $totalRows,
            'total_pages' => $totalPages,
            'has_prev' => $page > 1,
            'has_next' => $page < $totalPages,
        ],
    ];
}

進階：可複用分頁類（支援 JS 呼叫）

totalNum = $totalNum;
        $this->pageSize = $pageSize;
        $this->pageNo = max(1, $pageNo);
        $this->pageData = $pageData;
        $this->jsFunction = $jsFunction;

        $this->pageCount = max(1, (int)ceil($this->totalNum / $this->pageSize));
        $this->pageNo = min($this->pageNo, $this->pageCount);
        $this->offset = ($this->pageNo - 1) * $this->pageSize;
        $this->hasPrev = $this->pageNo > 1;
        $this->hasNext = $this->pageNo < $this->pageCount;
        $this->pageList = $this->generatePageList();
    }

    private function generatePageList(): array {
        $list = [];
        if ($this->pageCount <= 9) {
            $list = range(1, $this->pageCount);
        } else {
            if ($this->pageNo <= 4) {
                $list = array_merge(range(1, 5), [-1], [$this->pageCount]);
            } elseif ($this->pageNo > $this->pageCount - 4) {
                $list = array_merge([1], [-1], range($this->pageCount - 4, $this->pageCount));
            } else {
                $list = array_merge(
                    [1], [-1],
                    range($this->pageNo - 2, $this->pageNo + 2),
                    [-1], [$this->pageCount]
                );
            }
        }
        return $list;
    }

    public function render(): string {
        if ($this->pageCount <= 1) return '';

        $html = "<div class='pagination'><div class='page-bottom'>";
        if ($this->hasPrev) {
            $html .= "<a class='page-prev' href='javascript:{$this->jsFunction}(" . ($this->pageNo - 1) . ")'>上一頁</a>";
        }
        foreach ($this->pageList as $p) {
            if ($p === -1) {
                $html .= "<span class='page-break'>...</span>";
            } elseif ($p == $this->pageNo) {
                $html .= "<span class='page-cur'>{$p}</span>";
            } else {
                $html .= "<a href='javascript:{$this->jsFunction}({$p})'>{$p}</a>";
            }
        }
        if ($this->hasNext) {
            $html .= "<a class='page-next' href='javascript:{$this->jsFunction}(" . ($this->pageNo + 1) . ")'>下一頁</a>";
        }
        $html .= "</div></div>";
        return $html;
    }
}

使用範例

prepare('SELECT * FROM news ORDER BY created_at DESC LIMIT :offset, :pageSize');
$stmt->execute(['offset' => $offset, 'pageSize' => $pageSize]);
$pageData = $stmt->fetchAll(PDO::FETCH_ASSOC);

// 總筆數
$total = $pdo->query('SELECT COUNT(*) FROM news')->fetchColumn();

// 建立分頁器
$paginator = new Paginator($total, $pageSize, $pageNo, $pageData, 'loadPage');

// 輸出分頁 HTML
echo $paginator->render();

前端 JS 配合（AJAX 翻頁）

結語

分頁核心在於 LIMIT offset, size 與總筆數查詢。封裝為可複用類別，支援伺服端渲染與 AJAX 兩種模式，並提供彈性的頁碼顯示演算法（省略號、邊界頁碼），能滿足大多數專案需求。