Question

我一直在努力为我的网络应用程序找出分页脚本的最佳解决方案。我已经进行了很好的研究，知道在使用rownum的SQL Server中有LIMIT的替代方法，但我无法得到我希望按照我的方式做的结果。这是我的旧代码，如果一个表包含数百个产品，这将是一个非常糟糕的方法，我所做的只是改变rownums中的查询范围：

$page = $_GET['pageinfo'];

    if (!(isset($page))) 

     { 
        $page=1;
     } 


        if($page==1)
        {

        $query1 = " SELECT *
        FROM   (SELECT ROW_NUMBER() OVER(ORDER BY range) AS 
               rownum, productID, productName, category, range, price, picture, description FROM products) AS products1
        WHERE  rownum >= 0 AND rownum <= 9";


        $result1 = sqlsrv_query( $conn, $query1, array(), array( "Scrollable" => SQLSRV_CURSOR_KEYSET ));



            if( $result1 === false)
            {
                 echo "Error in query preparation/execution.\n";
                 die( print_r( sqlsrv_errors(), true));
            }


                 while( $row = sqlsrv_fetch_array ( $result1, SQLSRV_FETCH_ASSOC))
            {
                echo '<p class="productsContent">'.$row['productName'];
                echo '<br/>'.$row['description'];
                echo '<br/>'.$row['category'];
                echo '<br/>'.$row['range'];
                echo '<br/>&pound;'.$row['price'];
                echo '<br/><br/><a href="products.php?productID='.$row['productID'].'"><img  src="' . $row['picture'] .'"   alt="' . $row['productName'] .'"   title="' . $row['productName'] .'"   /></a>';

                echo '<br/><br/></p>';
            }

        echo'<a href="products.php?pageinfo=2&amp;main=go">Page two</a>';
    }

    else if($page==2)
        {

        $query2 = " SELECT *
        FROM   (SELECT ROW_NUMBER() OVER(ORDER BY range) AS 
               rownum, productID, productName, category, range, price, picture, description FROM products) AS products1
        WHERE  rownum >= 10 AND rownum <= 20";


        $result2 = sqlsrv_query( $conn, $query2, array(), array( "Scrollable" => SQLSRV_CURSOR_KEYSET ));


    if( $result2 === false)
    {
         echo "Error in query preparation/execution.\n";
         die( print_r( sqlsrv_errors(), true));
    }


         while( $row = sqlsrv_fetch_array ( $result2, SQLSRV_FETCH_ASSOC))
    {
        echo '<p class="productsContent">'.$row['productName'];
        echo '<br/>'.$row['description'];
        echo '<br/>'.$row['category'];
        echo '<br/>'.$row['range'];
        echo '<br/>&pound;'.$row['price'];
        echo '<br/><br/><a href="products.php?productID='.$row['productID'].'"><img  src="' . $row['picture'] .'"   alt="' . $row['productName'] .'"   title="' . $row['productName'] .'"   /></a>';
        echo '<br/><br/></p>';

    }

         echo'<a href="products.php?pageinfo=1&amp;main=go">Page one</a>';

        }

    }

我已经按照了一个似乎有更好的解决方案的教程，但这是使用MySQL完成的，我使用的是SQL Server。这是我最新的代码：

 if (!(isset($pagenum))) 

     { 

     $pagenum = 1; 

     } 

         $page_rows = 9; 


         $stmt = sqlsrv_query( $conn, "select * from products $max" , array(), array( "Scrollable" => SQLSRV_CURSOR_KEYSET ));

            $rows = sqlsrv_num_rows( $stmt );

        $last = ceil($rows/$page_rows); 

                 if ($pagenum < 1) 

                     { 

                     $pagenum = 1; 

                     } 

                     elseif ($pagenum > $last) 

                     { 

                     $pagenum = $last; 

                     } 


         $max = 'limit ' .($pagenum - 1) * $page_rows .',' .$page_rows; 




                 while($info = sqlsrv_fetch_array( $stmt )) 

                 { 

                 Print $info['description']; 

                 echo "<br>";

                 } 

                 echo "<p>";


                     echo " --Page $pagenum of $last-- <p>";


                     echo " --Page $pagenum of $last-- <p>";


                     if ($pagenum == 1) 

                     {

                     } 

                     else 

                     {

                     echo " <a href='{$_SERVER['PHP_SELF']}?pagenum=1'> <<-First</a> ";

                     echo " ";

                     $previous = $pagenum-1;

                     echo " <a href='{$_SERVER['PHP_SELF']}?pagenum=$previous'> <-Previous</a> ";

                     } 


                    if ($pagenum == $last) 

                             {

                             } 

                             else {

                             $next = $pagenum+1;

                             echo " <a href='{$_SERVER['PHP_SELF']}?pagenum=$next'>Next -></a> ";

                             echo " ";

                             echo " <a href='{$_SERVER['PHP_SELF']}?pagenum=$last'>Last ->></a> ";

                             }

你可以看到它使用'限制'，我花了一段时间才意识到SQL Server不支持它。

所以我的问题是混合我的两种方法，我只是无法弄清楚如何有效地做到这一点，任何建议都将不胜感激。

Answer 1

这是一个非常通用的模板。

with rnkd as (select row_number() over (order by [yoursortfield]) rn, *
              from   [yourtable])
select *
from   rnkd
where  rn >= @start and rn < @end
order  by rn

或者，您可以使用顶级运算符。这里的订单很重要：

with rnkd as (select row_number() over (order by [yoursortfield]) rn, *
              from   [yourtable])
select top (@pagesize) *
from   rnkd
where  rn >= @start
order  by rn

或者，您可以避免使用CTE并执行派生表，但我个人更喜欢CTE。

select top (@pagesize) *
from   (select row_number() over (order by [yoursortfield]) rn, *
        from   [yourtable]) rnkd
where  rn >= @start
order  by rn

有没有更好的方法在SQL Server 2008中执行与LIMIT类似的操作？

1 个答案: