在查询中添加num_rows时出错

Question

这个旧查询工作正常，但是当我添加

时

        $statement->store_result();
        $rows = $statement->num_rows;   

添加store_result和num_rows后，我收到此错误消息：

  

致命错误：在布尔值

上调用成员函数fetch_assoc（）

我不能使用bind_result。

有没有办法解决这个问题，还是应该为num_rows进行第二次查询？

旧查询：

$mw_gegevens_qry = "SELECT
                        * 
                    FROM 
                        mw_gegevens
                    WHERE   
                        mw_gegevens_persnr=?
                    AND     
                        mw_gegevens_pass=?
                    AND
                        mw_gegevens_pass!='' 
                            ";
    $statement = $connection->prepare($mw_gegevens_qry);
    if($qry === false){
    echo "Query error:.". $connection->error();
    }else{  
        $statement->bind_param('is', $user, $userpassword);   
        $statement->execute();
        $result = $statement->get_result(); 
        $mwgegevens = $result->fetch_assoc();

新查询

$mw_gegevens_qry = "SELECT
                        * 
                    FROM 
                        mw_gegevens
                    WHERE   
                        mw_gegevens_persnr=?
                    AND     
                        mw_gegevens_pass=?
                    AND
                        mw_gegevens_pass!='' 
                            ";
    $statement = $connection->prepare($mw_gegevens_qry);
    if($qry === false){
    echo "Query error:.". $connection->error();
    }else{  
        $statement->bind_param('is', $user, $userpassword);   
        $statement->execute();
        $statement->store_result();
        $rows = $statement->num_rows;   
        $result = $statement->get_result(); 
        $mwgegevens = $result->fetch_assoc();

Answer 1

$mw_gegevens_qry = "
            SELECT
                * 
            FROM 
                mw_gegevens
            WHERE   
                mw_gegevens_persnr=?
            AND     
                mw_gegevens_pass=?
            AND
                mw_gegevens_pass!='' 
                ";
    $statement = $connection->prepare($mw_gegevens_qry);
    if($qry === false){
    echo "Query error:.". $connection->error();
    }else{  
        $statement->bind_param('is', $user, $userpassword);   
        $statement->execute();
        $result = $statement->get_result(); 
        $rows = $result->num_rows;
        $mwgegevens = $result->fetch_assoc();