如果mysql_num_rows返回0结果时无法识别语句 [英] If statement not recognising when mysql_num_rows returns 0 results

问题描述

我正在尝试运行代码，似乎给了我错误的结果，我尝试了很多方法，但仍然没有得到.在这里:

I am trying to run the code and it seems to be given me wrong result, I tried many ways and still not getting it. Here it is:

//compares vid num to db been result
$id = mysql_real_escape_string(@$_GET['g']);
$vid = mysql_real_escape_string(@$_GET['v']);
$sql= mysql_query("SELECT videos.* FROM videos WHERE videos.email = 
                 (SELECT email FROM page WHERE page.user_id = '$id') 
                  AND videos.videoid = '$vid'");

if (mysql_num_rows($sql) == 0) { echo "none";} else echo "it exists";

如果我在phpmyadmin中运行查询，它将运行正确，但是在PHP中运行时，结果是offfff，即使phpmyadmin返回0(正确)，它也会不断回显它的存在.我一直试图弄清楚这一点，却一无所获.我尝试了!isset($sql)相反的东西.

If I run the query in phpmyadmin it runs correct, but when run in PHP the result is offfff, it keeps echoing it exists even when phpmyadmin returns 0 which is correct. I have been trying to figure this out and keeps getting nothing. I have tried !isset($sql) oppositely the something.

推荐答案

if ( $sql ) // valid result
{
    if ( mysql_num_rows( $sql ) > 0 ) // more than 0 records
        echo "it exists";
    else
        echo "none";
}

如果上面的代码仍然给您带来问题，则您的mysql查询中的某些内容导致找到结果.

If the above code still gives you a problem, then something in your mysql query is causing a result to be found.

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