SQL加入SUM沒有正常工作

Question

我遇到一個問題產生與我的查詢結果。我想要從與主表相關的另一個表中生成行結果的SUM。

我沒有輸出的是付款總額和應付款總額。

• 問題＃1 - 我無法產生正確的付款輸出。 查詢似乎產生公式numrows * sum_of_payments

• 問題＃2 - 我無法產生總應付款的產出。

我正在使用Codeigniter 3，這是我的模型。

function fetch_billing_records($case_id, $patient_id, $status) { 

     $this->db->join('cases', 'cases.id = billing.case_id', 'left'); 
     $this->db->join('patients', 'patients.id = cases.patient_id', 'left');    
     $this->db->join('users', 'users.username = billing.user', 'left'); 
     $this->db->join('billing_payments', 'billing_payments.billing_id = billing.id', 'left'); 
     $this->db->join('billing_items', 'billing_items.billing_id = billing.id', 'left'); 
     $this->db->join('services', 'services.title = billing_items.service', 'left'); 
     $this->db->select(' 
      billing.id, 
      billing.remarks, 
      billing.status, 
      billing.created_at, 
      billing.updated_at, 
      users.name as user, 
      users.username, 
      cases.id as case_id, 
      cases.title as case_title, 
      patients.id as patient_id, 
      CONCAT(patients.lastname, ", ", patients.fullname) as patient_name, 
      SUM(billing_payments.amount) as payments, 
      SUM((services.amount - billing_items.discount)*billing_items.qty) as payables 
     '); 

     if(is_int($case_id)) { 
      $this->db->where('billing.case_id', $case_id);   
     } 

     if(is_int($patient_id)) { 
      $this->db->where('patients.id', $patient_id); 
     } 

     if(is_int($status)) { 
      $this->db->where('billing.status', $status); 
     } 

     $this->db->group_by('billing.id'); 
     $this->db->where('billing.is_deleted', 0); 

     $query = $this->db->get("billing"); 

     log_message('error', $this->db->last_query()); 
     if ($query->num_rows() > 0) { 
      return $query->result_array(); 
     } 

     return false; 

} 

我保存上次查詢和登錄助手的最後一個查詢，它似乎爲我實例的查詢是

SELECT `billing`.`id`, `billing`.`remarks`, `billing`.`status`, `billing`.`created_at`, `billing`.`updated_at`, `users`.`name` as `user`, `users`.`username`, `cases`.`id` as `case_id`, `cases`.`title` as `case_title`, `patients`.`id` as `patient_id`, CONCAT(patients.lastname, ", ", patients.fullname) as patient_name, SUM(billing_payments.amount) as payments, SUM((services.amount - billing_items.discount)*billing_items.qty) as payables 
FROM `billing` 
LEFT JOIN `cases` ON `cases`.`id` = `billing`.`case_id` 
LEFT JOIN `patients` ON `patients`.`id` = `cases`.`patient_id` 
LEFT JOIN `users` ON `users`.`username` = `billing`.`user` 
LEFT JOIN `billing_payments` ON `billing_payments`.`billing_id` = `billing`.`id` 
LEFT JOIN `billing_items` ON `billing_items`.`billing_id` = `billing`.`id` 
LEFT JOIN `services` ON `services`.`title` = `billing_items`.`service` 
WHERE `billing`.`is_deleted` =0 

爲了更引導你用我現在的問題，這是架構相關表格：

，這是整個數據庫的模式。

Answer 1

使用group by statement。因爲mysql集合函數與group通過很好。如果你想針對病人的開單金額，然後使用以下查詢

SELECT 
    `billing`.`id`, 
    `billing`.`remarks`, 
    `billing`.`status`, 
    `billing`.`created_at`, 
    `billing`.`updated_at`, ` 
    users`.`name` as `user`, 
    `users`.`username`, 
    `cases`.`id` as `case_id`, 
    `cases`.`title` as `case_title`, 
    `patients`.`id` as `patient_id`, 
    CONCAT(patients.lastname, ", ", patients.fullname) as patient_name, 
    SUM(billing_payments.amount) as payments, 
    SUM((services.amount - billing_items.discount)*billing_items.qty) as payables 
FROM `billing` 
    LEFT JOIN `cases` ON `cases`.`id` = `billing`.`case_id` 
    LEFT JOIN `patients` ON `patients`.`id` = `cases`.`patient_id` 
    LEFT JOIN `users` ON `users`.`username` = `billing`.`user` 
    LEFT JOIN `billing_payments` ON `billing_payments`.`billing_id` = `billing`.`id` 
    LEFT JOIN `billing_items` ON `billing_items`.`billing_id` = `billing`.`id` 
    LEFT JOIN `services` ON `services`.`title` = `billing_items`.`service` 
WHERE `billing`.`is_deleted` =0 
GROUP BY patients.id