如何从关系数据库codeigniter获取数据

Question

As i was using comma separated values in DB every one suggested me to normalize table so i normalized my table now my table looks like this

tuitor table
tuitor_id | name | mobile |etc
   1      | xyz  |14562547|anyinputs
   2      |abc   |47545875|text
   3      |abd   |47854874|yyy

now my normalized table is tuitor_keyword

tuitor_keyword_id | id_tuitor | id_keyword
   1              |   1       |123
   2              |   1       |124
   3              |   2       |123
   4              |   2       |155
   5              |   1       |187  

while retrieving any tuitor i want keywords in comma like for id_tuitor=1 it should be 123,124

this is the query what i am using

        $this->db->select('*')->from('tuitor');  
        $this->db->join('tuitor_keyword','tuitor.tuitor_id =  tuitor_keyword.id_tuitor','left');

  $query=$this->db->get();
        return $result = $query->result_array();

It is creating new array for for tuitor_keyword_id what should i do please correct me i know i have done plenty of mistakes

Answer 1

CONCAT_GROUP is a solution for you:

$this->db->query('SELECT id_tuitor, CONCAT_GROUP(id_keyword) AS gr FROM tuitor_keyword GROUP BY id_tuitor');

or:

$this->db->select('id_tuitor, CONCAT_GROUP(id_keyword) AS gr', false)->from('tuitor_keyword')->group_by('id_tuitor');