Cómo crear el Libro Mayor/Cuenta T usando PHP Mysql

public function getDebits(){    
    $data   =   array(
                'debit_side.account_code DebitCode',
                'group_concat(distinct accounts.name) as DebitAccount',
                'group_concat(debit_side.amount) as DebitAmount',
                'group_concat(transaction_info.voucher_date) as DebitVoucherDate'
                );
    $this->db->select($data);
    $this->db->from('accounts');
    $this->db->join('credit_side','accounts.code = credit_side.account_code','left');
    $this->db->join('debit_side','debit_side.transaction_id_dr = credit_side.transaction_id_cr','left');
    $this->db->join('transaction_info','transaction_info.transaction_id = credit_side.transaction_id_cr','left');
    $this->db->group_by('debit_side.account_code');
    $this->db->order_by('debit_side.account_code','ASC');
    $query  =   $this->db->get();
    return  $query->result_array();
}


public  function getCredits()
{
    $data   =   array(
                'credit_side.account_code CreditCode',
                'group_concat(distinct accounts.name) as CreditAccount',
                'group_concat(credit_side.amount) as CreditAmount',
                'group_concat(transaction_info.voucher_date) as CreditVoucherDate'
                );
    $this->db->select($data);
    $this->db->from('accounts');
    $this->db->join('debit_side','accounts.code = debit_side.account_code','left');
    $this->db->join('credit_side','debit_side.transaction_id_dr = credit_side.transaction_id_cr','left');
    $this->db->join('transaction_info','transaction_info.transaction_id = credit_side.transaction_id_cr','left');
    $this->db->group_by('credit_side.account_code');
    $this->db->order_by('credit_side.account_code','ASC');
    $query  =   $this->db->get();
    return  $query->result_array();
}

Lo siento por la respuesta tardía, pero esto es lo perfecto que quieres probar antes de hacer nada. Quería crear un archivo de vista para esto, pero parece ser complicado y lleva más tiempo que en este momento.

EDITADO

Esta solución podría estar atormentándolo en la vista, ya que la he probado. Sin embargo, he intentado combinar estas dos consultas y lo he logrado. La consulta puede parecer algo compleja, pero está obteniendo los resultados perfectos. Aquí está

$data   =   array(
                  'debit_side.account_code    Code',
                  'group_concat(distinct accounts.name) as DebitAccount',
                  'group_concat(debit_side.amount) as DebitAmount',
                  'group_concat(transaction_info.voucher_date) as DebitVoucherDate',
                  '(SELECT group_concat(distinct accounts.name) as CreditAccount FROM (accounts)
                    left JOIN debit_side ON accounts.code = debit_side.account_code
                    left JOIN credit_side ON debit_side.transaction_id_dr = credit_side.transaction_id_cr
                    left JOIN transaction_info ON transaction_info.transaction_id = credit_side.transaction_id_cr
                    group by credit_side.account_code
                    having credit_side.account_code = `Code`) as CreditAccount',
                  '(SELECT  group_concat(credit_side.amount) as CreditAmount FROM (accounts)
                     left JOIN debit_side ON accounts.code = debit_side.account_code
                     left JOIN credit_side ON debit_side.transaction_id_dr = credit_side.transaction_id_cr
                     left JOIN transaction_info ON transaction_info.transaction_id = credit_side.transaction_id_cr
                   group by credit_side.account_code
                   having credit_side.account_code = `Code`) as CreditAmount',  
                  '(SELECT  group_concat(transaction_info.voucher_date) as CreditVoucherDate FROM (accounts)
                    left JOIN debit_side ON accounts.code = debit_side.account_code
                    left JOIN credit_side ON debit_side.transaction_id_dr = credit_side.transaction_id_cr
                    left JOIN transaction_info ON transaction_info.transaction_id = credit_side.transaction_id_cr
                    group by credit_side.account_code
                    having credit_side.account_code = `Code`) as CreditVoucherDate'

                );
    $this->db->select($data);
    $this->db->from('accounts');
    $this->db->join('credit_side','accounts.code = credit_side.account_code','left');
    $this->db->join('debit_side','debit_side.transaction_id_dr = credit_side.transaction_id_cr','left');
    $this->db->join('transaction_info','transaction_info.transaction_id = credit_side.transaction_id_cr','left');
    $this->db->group_by('debit_side.account_code');
    $this->db->order_by('debit_side.account_code','ASC');
    $query  =   $this->db->get();
    return  $query->result_array();

Aunque esta consulta funciona bien, aquí hay una versión modificada y optimizada de esta consulta. Realmente aprendí cosas de esta consulta. Deberías echarle un vistazo también

Extraño comportamiento de Agrupar por en consulta que debe optimizarse