sql语句报错

$sql="select * from `abc_dem` where `p6`="."$gameid"." and `st`=1 and `p3`>=".$num;

报错如下：
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'and st=1 and p3>=' at line 1
select * from ***_dem where p6= and st=1 and p3>= sql mysql
[解决办法]
$sql="select * from `abc_dem` where `p6`='$gameid' and `st`=1 and `p3`>='$num'";