Multiple Joins in Codeigniter

Question

I\'m new to building databases and I\'m trying to do a JOIN based on a having three database tables.

Table A = ID, Name, etc
Table B = ID, Name, etc
Table C          


        

Answer 1

$this->db->select('*');
$this->db->from('TableA AS A');// I use aliasing make joins easier
$this->db->join('TableC AS C', 'A.ID = C.TableAId', 'INNER');
$this->db->join('TableB AS B', 'B.ID = C.TableBId', 'INNER');
$result = $this->db->get();

The join function works like this: join('TableName', 'ON condition', 'Type of join');

The equivilent sql:

SELECT *
FROM TableA AS A
    INNER JOIN TableC AS C
    ON C.TableAId = A.ID
    INNER JOIN TableB AS B
    ON B.ID = C.ID

I found that writing the SQL first, testing it, then converting to the active record style minimizes error.