MySQL中数组变量作为查询参数sql语句该如何写？

$arr = new Array("1","2","3")

$sql = "select * from tab where id>".$arr[0]." and id<>".$arr[2]

简单举了个例子

"SELECT username,password FROM user where='userName'")

SQL语句有问题

res = mysql_query(my_connection, "SELECT username,password FROM user where userName='"+userName+"'")//

你没有注意异常的信息

---