Question

我试图开发一个分页系统，我有一个奇怪的问题。我在下面有这个代码，代码总是进入我的if条件，说有0结果。但是当我执行print_r时，我的sql语句是正确的。你能看出我有没有看到错误的东西？

 $pag = (empty($_GET['pag']) ? '1' : $_GET['pag']);
            $max = 3;
            $begin = ($pag * $max) - $max;
            $readPages = $pdo->prepare("SELECT * FROM pages where id_numb IS null LIMIT :beg,:ma");  
            $readPages->bindValue(":beg", $begin);
            $readPages->bindValue(":ma", $max);    
            $readPages->execute();
            $num_rows = $readPages->rowCount();

            if(!$num_rows >= 1)
            {
                echo '0 results';
            }

Answer 1

always enable exception mode让PDO收到SQL错误通知
对于LIMIT条款，您必须set PDO::PARAM_INT explicitly

Answer 2

        $num_rows = readPages->rowCount();
                    ^---missing $. A constant object? no way...
        print_r($lerCat);
                 ^^^^^^--- undefined variable

我的pdo阅读声明无法正常工作

2 个答案: