MySQL INNER JOIN 3個表格，也使用INNER JOIN DELETE使用

Question

我真的很爲這個任務苦苦掙扎，所以任何幫助或指導都將非常感激。

的表格：

  module_uploads 
      +--------------------------+ 
      | upload_id | upload_name | 
      +--------------------------+ 
      | 1006 | 12.png  | 
      | 1007 | 18.png  | 
      +--------------------------+ 

      module_timelimit 
      +------------------------------------------------+ 
      | upload_id | email  | expires    | 
      +------------------------------------------------+ 
      | 1006 | me@me.com | 2014-05-22 16:34:54 | 
      | 1007 | me12@me.com | 2015-05-20 20:34:54 | 
      +------------------------------------------------+ 

      module_fieldvals 
      -----------------------------------------+ 
      | upload_id | fld_id | value   | 
      -----------------------------------------+ 
      | 1006 | 2  | me@me.com  | 
      | 1006 | 0  | mcdda8fbr  | 
      | 1007 | 0  | mcdda8fbr  | 
      | 1007 | 2  | me12@me.com  | 
      -----------------------------------------+ 

行，所以我想加入基於在到期日已經通過upload_id的3個表，刪除文件，發送電子郵件，然後刪除所有數據。我有2個問題：

• 我只能似乎加入使用fld_id = 2，他們按到期日的表。能夠刪除fld_id = 2和fld_id = 0的數據會很好，但我好像得到了重複的電子郵件，因爲while循環迭代了4次而不是2次。
• 我無法確定如何刪除數據
• 有沒有辦法只用一個SQL查詢來完成它？

這裏是我到目前爲止的代碼：

  $database  = cmsms()->getDb(); 
      $now   = $database->DbTimeStamp(time()); 
      $query   = " 
          SELECT 
           module_uploads.upload_id, 
           module_uploads.upload_name, 
           module_fieldvals.upload_id, 
           module_fieldvals.fld_id, 
           module_fieldvals.value, 
           module_timelimit.upload_id, 
           module_timelimit.email, 
           module_timelimit.expires 
          FROM 
           module_timelimit 
          INNER JOIN module_uploads 
           ON module_timelimit.upload_id = module_uploads.upload_id 
          INNER JOIN module_fieldvals 
           ON module_timelimit.upload_id = module_fieldvals.upload_id 
          WHERE module_timelimit.expires < $now AND module_fieldvals.fld_id = 2 
          GROUP BY module_timelimit.expires"; 

      $result   = mysql_query($query); 

      // Delete the rows 
      $query_deletion = " 
          DELETE cms_module_uploads_timelimit, cms_module_uploads, cms_module_uploads_fieldvals 
          FROM 
           cms_module_uploads_timelimit 
          INNER JOIN cms_module_uploads 
           ON cms_module_uploads_timelimit.upload_id = cms_module_uploads.upload_id 
          INNER JOIN cms_module_uploads_fieldvals 
           ON cms_module_uploads_timelimit.upload_id = cms_module_uploads_fieldvals.upload_id 
          WHERE cms_module_uploads_timelimit.expires < $now AND cms_module_uploads_fieldvals.fld_id = 2 
          GROUP BY cms_module_uploads_timelimit.expires"; 

      $delete_result = mysql_query($query_deletion);    

      // Check if any queries failed    
      if(!$result || !$delete_result) { 
       if (!$result) exit("Error - The selection query did not succeed"); 
       if (!$delete_result) exit("Error - The deletion query did not succeed"); 
      } else { 

       // set up the settings for FTP to delete file 
       $ftp_server = 'xxxxxxx'; 
       $ftpuser = 'xxxxxx'; 
       $ftppass = 'xxxxxx'; 

       // set up basic connection 
       $conn_id = ftp_connect($ftp_server); 

       // login with username and password 
       $login_result = ftp_login($conn_id, $ftpuser, $ftppass); 

       if ((!$conn_id) || (!$login_result)) { 

        echo "Error could not connect to FTP"; 

       } else { 

        while ($row = mysql_fetch_array($result)) { 
         $upload_id = $row['upload_id']; 
         $file = $row['upload_name']; 
         $email = $row['value']; 

         // Check if file and email exists 
         if(isset($file) && isset($email)) { 

          $file = '/uploads/adverts/'.$file; 

          // Delete file 
          if (ftp_delete($conn_id, $file)) { 
           echo "$file deleted successfully\n"; 
          } else { 
           echo "could not delete $file\n"; 
          } 

          // Send email using CMSMS GCB 
          $cmsmailer->Send(); 
         } 
        } 
       } 

       // close the connection 
       ftp_close($conn_id); 
      } 

Answer 1

檢查表的名字，因爲他們在你的SELECT和DELETE不同。

雖然有來自多個表中刪除以上的格式，你的主要問題是，你必須從DELETE語句刪除的GROUP BY條款：

DELETE 
FROM cms_module_uploads_timelimit, cms_module_uploads, cms_module_uploads_fieldvals 
USING cms_module_uploads_timelimit 
INNER JOIN cms_module_uploads 
    ON cms_module_uploads_timelimit.upload_id = cms_module_uploads.upload_id 
INNER JOIN cms_module_uploads_fieldvals 
    ON cms_module_uploads_timelimit.upload_id = cms_module_uploads_fieldvals.upload_id 
WHERE cms_module_uploads_timelimit.expires < $now 
    AND cms_module_uploads_fieldvals.fld_id = 2