在mysqli->query()语句中遇到的两个问题，求大神解答下

Question

<?php
$mysqli=new mysqli("localhost", "root", "", "test");
if($mysqli->connect_error){
die( "connection failed".$mysqli->connect_error);
}else{
echo "connection succed";
}
$mysqli->query("set names utf8");
$sql="select * from emp limit3,3";
$sql1="select * from emp limit&nbsp3,3";
$res=$mysqli->query($sql);
$res1=$mysqli->query($sq1);
var_dump($res);
var_dump($res1);
$res->free();
$res1->free();
$mysqli->close();
?>

这两句话都无法执行成功,求大神指点
$sql="select * from emp limit3,3";
$sql1="select * from emp limit&nbsp3,3";