codeigniter change complex query into active record - sql

Question

I have a codeigniter app.
My active record syntax works perfectly and is:
function get_as_09($q){
$this->db->select('m3');
$this->db->where('ProductCode', $q);
$query = $this->db->get('ProductList');
if($query->num_rows > 0){
foreach ($query->result_array() as $row){
$row_set[] = htmlentities(stripslashes($row['m3'])); //build an array
}
return $row_set;
}
}
This is effectively
select 'm3' from 'ProductList' where ProductCode='$1'
What I need to do is convert the below query into an active record type query and return it to the controller as per above active record syntax:
select length from
(SELECT
[Length]
,CONCAT(([width]*1000),([thickness]*1000),REPLACE([ProductCode],concat(([width]*1000),([thickness]*1000),REPLACE((convert(varchar,convert(decimal(8,1),length))),'.','')),'')) as options
FROM [dbo].[dbo].[ProductList]) as p
where options='25100cr' order by length
I picture something like below but this does not work.
$this->db->select(length);
$this->db->from(SELECT [Length],CONCAT(([width]*1000),([thickness]*1000),REPLACE[ProductCode],concat(([width]*1000),([thickness]*1000),REPLACE((convert(varchar,convert(decimal(8,1),length))),'.','')),'')) as options
FROM [dbo].[dbo].[ProductList]);
$this->db->where(options, $q);
$this->db->order(length, desc);
Help appreciated as always. Thanks again.

Answer 1

You can use sub query way of codeigniter to do this for this purpose you will have to hack codeigniter. like this
Go to system/database/DB_active_rec.php Remove public or protected keyword from these functions
public function _compile_select($select_override = FALSE)
public function _reset_select()
Now subquery writing in available And now here is your query with active record
$select = array(
'Length'
'CONCAT(([width]*1000)',
'thickness * 1000',
'REPLACE(ProductCode, concat((width*1000),(thickness*1000),REPLACE((convert(varchar,convert(decimal(8,1),length))),'.','')),'')) as options'
);
$this->db->select($select);
$this->db->from('ProductList');
$Subquery = $this->db->_compile_select();
$this->db->_reset_select();
$this->db->select('length');
$this->db->from("($Subquery)");
$this->db->where('options','25100cr');
$this->db->order_by('length');
And the thing is done. Cheers!!!
Note : While using sub queries you must use
$this->db->from('myTable')
instead of
$this->db->get('myTable')
which runs the query.
Source