mysql - 不等于 codeigniter 中的条件不起作用

Question

不等于条件在我的 codeigniter sql 查询中不起作用。我也尝试过 <> 但这也不起作用请有人帮助解决这个问题。输出以等于条件显示

 $result = $this->db->query("select a.user_email  from users as a, result as b where b.exam_id = '".$exam_id."' and a.user_id  != b.user_id  and  a.active =  1 and a.user_role_id != 1 group by a.user_id")
->result();

Answer 1

尝试使用它，因为编译器无法清楚地理解您的查询，这就是它给出错误输出的原因。

$query="select a.user_email  "
        . "from users as a, result as b "
        . "where b.exam_id = '".$exam_id."'"
        ."a.active =  1 and"
        . "(a.user_id  != b.user_id)  "
        . "and "
        . "(a.user_role_id != 1 group by a.user_id)"