检查记录存在于mysql php中

Question

请参阅我已经检查了旧线程，但没有帮助。

这是我的代码，看起来还可以，但是会出现错误： Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given

码：

function getPnr()
{
    $con = mysqli_connect('127.0.0.1', 'root', '', 'safari');
    if (mysqli_connect_errno())
    {
        echo "Failed to connect to MySQL: " . mysqli_connect_error();
        return;
    }
    $pnr = mt_rand(1111111111, 99999999999);                
    $result = mysqli_query($con,"SELECT pnr from tbl_user where pnr = '".$pnr."'");
    if(mysqli_num_rows($result)>0)
        echo "emtpy";//getPnr();
    else
        echo $pnr;
}

怎么了

更新的代码：

function getPnr()

{

$con = mysqli_connect('127.0.0.1', 'root', '', 'safari');
if (mysqli_connect_errno())
{
    echo "Failed to connect to MySQL: " . mysqli_connect_error();
    return;
}
$pnr = mt_rand(1111111111, 99999999999);                
$result = mysqli_query($con,"SELECT user_pnr from tbl_user where user_pnr = '".$pnr."'") or die(mysqli_error($con);
if(mysqli_num_rows($result)>0)
    echo "emtpy";//getPnr();
else
    echo $pnr;

返回; }

新错误：

Parse error: syntax error, unexpected ';' in F:\\wamp\\www\\safari\\REST_APIs_for_RedBus\\main.php on line 104

Answer 1

这意味着您的sql查询无法执行。 尝试用您的代码添加错误处理，然后您将获得清晰的错误SQL消息

 $result = mysqli_query($con,"SELECT pnr from tbl_user where pnr = '".$pnr."'") or die(mysqli_error($con));