在Codeigniter中使用group_by选择（'*'）

Question

I am working in codeigniter. My problem is i want to show all rows having same id. But when i perform group_by it only outputs one row of that group.

below is my model

function category_content(){
        $this->db->select('*');
        $this->db->from('category');
        $this->db->group_by('category_id');
        $query = $this->db->get();
        return $query->result_array();
    }

Please help.

Answer 1

As per the sql properties Group By groups all the matching records and will show you only one. It seems you want to sort them by id. Then its better to use order by

Answer 2

See the Example hope you will get to know this..

    tableA
    _____
    id  name    marks
    --  ----    ---
    1   x       25
    2   y       27
    1   z       30


    SELECT * FROM tableA group by id

OUTPUT:
1   x   25
2   y   27

in your case you should use WHERE clause.

    SELECT * FROM tableA WHERE id=1

OUTPUT:
1   x   25
1   z   30


    function category_content(){
            $this->db->select('*');
            $this->db->from('category');
            $this->db->where($category_id);
            $query = $this->db->get();
            return $query->result_array();
        }

https://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html