Codeigniter query generating multiple rows

Question

Codeigniter:

public function get_customers(){
    $this->db->select('*,customer.ID as ID,customer.Create_date as Create_date,transport.Name as Transporter, state.Name as State, city.Name as City, area.Name as Area, shipping_state.Name as Shipping_state, shipping_city.Name as Shipping_city, shipping_area.Name as Shipping_area');
    $this->db->from('customer');
    $this->db->join('transport','transport.ID = customer.Transporter','LEFT');
    $this->db->join('state','state.ID = customer.State','LEFT');
    $this->db->join('state as shipping_state','state.ID = customer.Shipping_state','LEFT');
    $this->db->join('city','city.ID = customer.City','LEFT');
    $this->db->join('city as shipping_city','city.ID = customer.Shipping_city','LEFT');
    $this->db->join('area','area.ID = customer.Area','LEFT');
    $this->db->join('area as shipping_area','area.ID = customer.Shipping_area','LEFT');
    return $this->db->get()->result_array();
}

In customer table, there are 2 columns joining to the same table. in the customer table, there are only 1 rows. but when the query is generating it generating 1000+ rows. Anyone can please help me why it generating 1000+ rows and How can I resolve it.

Answer 1

You can always use $this->db->last_query() to visually understand and debug your code. It's good to do this, as you then you can start to understand how Active Record works.

$results = $this->db->get()->result_array();
log_message( "debug", "get_customers sql: ". $this->db->last_query() );
return $results;

So when you see your query in raw format; it looks like this:

SELECT 
    *,customer.ID as ID,
    customer.Create_date as Create_date,
    transport.Name as Transporter, 
    state.Name as State, 
    city.Name as City, 
    area.Name as Area, 
    shipping_state.Name as Shipping_state, 
    shipping_city.Name as Shipping_city, 
    shipping_area.Name as Shipping_area
FROM
    customer
LEFT JOIN transport ON ( 
    transport.ID = customer.Transporter
)
LEFT JOIN state ON ( 
    state.ID = customer.State
)
LEFT JOIN state as shipping_state ON ( 
    state.ID = customer.Shipping_state
)
LEFT JOIN city as shipping_state ON ( 
    city.ID = customer.City
)
LEFT JOIN city as shipping_city ON ( 
    city.ID = customer.Shipping_city
)
LEFT JOIN area ON ( 
    area.ID = customer.Area
)
LEFT JOIN area as shipping_area ON ( 
    area.ID = customer.Shipping_area
)

There's so many left joins here; that it will repeat any matched rows on each left join. It's hard to say without knowing the data, but it would appear that you would prefer to use a Hard Join.

Answer 2

With the amount of joins you have you might have to add a group by

so before your get add:

$this->db->group_by('customer.ID');