MySQLI和Select 1(MySQLI and Select 1)

 从数据库获取数据时，我的if语句没有按预期工作，即使我在该用户的数据库中有$ badgename，我得到“你得到一个新的徽章”。 但它没有穿上它。 
 
 我是MySQLI的新手，所以这可能是我错过的东西...... 
 
$numberofposts=$row['posts'];
$userid = $_SESSION['userid'];
$badgename = "Legend";

if($numberofposts >= 10){

$SQL = $mysqli->query("SELECT 1 FROM `badges` WHERE `mid`='$userid' AND 'badge' = '$badgename'");
$num = $SQL->num_rows;

if($num > 0){
 echo "You got a new badge";
 $mysqli->query("INSERT INTO badges ('mid', 'badge') VALUES ('$userid', '$badgename')");
}
else 
{
echo "You already have this badge";
}
 
 谢谢。 

When getting data from the databas my if statement isn't working as expected, even though I have the $badgename in the database for that user I got "You get a new badge". But it dosen't put it on. 
 
Im new to MySQLI so it's probably something I missed...
 
$numberofposts=$row['posts'];
$userid = $_SESSION['userid'];
$badgename = "Legend";

if($numberofposts >= 10){

$SQL = $mysqli->query("SELECT 1 FROM `badges` WHERE `mid`='$userid' AND 'badge' = '$badgename'");
$num = $SQL->num_rows;

if($num > 0){
 echo "You got a new badge";
 $mysqli->query("INSERT INTO badges ('mid', 'badge') VALUES ('$userid', '$badgename')");
}
else 
{
echo "You already have this badge";
}
 
Thanks. 

原文：https://stackoverflow.com/questions/21976406