php - MySQL转PDO(具体实例)

Question

我一直在逐页将整个网站从 MySQL 翻译成 PDO。在大多数情况下，此处的资源、示例和问题已被证明是学习差异和转换等价物的绝佳资源。但是，有一个声明我一直在苦苦思索，我觉得我可能需要就此向社区询问。它结合了 Query + Num_Rows 语句，我不确定是否有更简单的方法来重写它。我已经复制了下面页面的相关部分，但如果您需要更多信息，请告诉我。有问题的行是 $total_pages=mysql_num_rows(mysql_query('select author from '.$sql_bookshelfquery));

上述行所在的 PHP 文档部分(包括行本身)

$sql_bookshelfquery="trgbookshelf13 where trgbookshelf13.remove!=1 ";
    $sql_bookshelfquery.=$querylevel;
    $sql_bookshelfquery.=$isnew;



// How many adjacent pages should be shown on each side?
    $adjacents = 3;

    /* 
       First get total number of rows in data table. 
       If you have a WHERE clause in your query, make sure you mirror it here.
    */

    $total_pages=mysql_num_rows(mysql_query('select author from '.$sql_bookshelfquery));



    /* Setup vars for query. */
    $limit = 50;                                //how many items to show per page
    if($page) 
        $start = ($page - 1) * $limit;          //first item to display on this page
    else
        $start = 0;                             //if no page var is given, set start to 0

    /* Get data. */
        $sql_bookshelfquery.=$orderby;
    $sql_bookshelfquery.=" LIMIT $start, $limit";
    $sql_bookshelfquery="SELECT * FROM ".$sql_bookshelfquery;


    //$result = mysql_query($sql_bookshelfquery);
    $result = $dbh->query($sql_bookshelfquery);

Answer 1

我不知 Prop 体你的 PDO 变量，但像这样的东西应该可以工作:

$sql = "SELECT COUNT(`author`) FROM " . $sql_bookshelfquery; // Write SQL
$sth = $dbh->prepare($sql);  // Prepare query
$sth->execute(); // Execute query
$total_pages = $sth->fetchColumn(); // Fetch query result

干杯!