如何在此过程中构建动态查询

Question

我正在尝试使用mysql数据库中的存储过程构建动态查询，但仍然看到此错误。为什么呢？

1064 - 您的SQL语法出错;检查与MariaDB服务器版本对应的手册，以便在第7行

附近使用正确的语法

DROP PROCEDURE IF EXISTS mp_test;
CREATE PROCEDURE mp_test(
    IN PrStatus VARCHAR(255),
    IN PrStatusCode VARCHAR(255),
    IN PrProviderId VARCHAR(255),
    IN PrRow VARCHAR(255))
   BEGIN
      SET @Condition  = '';
      SET @Query = '   
      SELECT
      bitauth_users.fullname,
      tbservices.ServiceNameAR,
      tbservices.ServiceNameEN,
      tbservices.ServiceId,
      globrx.ProviderId,
      globrx.RequestDesc,
      TbServicesRequestsLog.status
        FROM tbservices, Tbservicesrequests globrx, 
        TbServicesRequestsLog, bitauth_users  
        WHERE  globrx.ProviderId = 'Prproviderid' ';

      IF PrStatus != '' THEN
         SET @Condition = CONCAT(' AND globrx.RequestId = TbServicesRequestsLog.RequestId');
         SET @Condition = CONCAT(' AND globrx.ServiceId = tbservices.ServiceId');
         SET @Condition = CONCAT(' AND bitauth_users.user_id = globrx.ReceiverId');
         SET @Condition = CONCAT(' AND globrx.RequestId = TbServicesRequestsLog.RequestId');
         SET @Condition = CONCAT('AND (SELECT status  FROM TbServicesRequestsLog,Tbservicesrequests AS subrx
                                  WHERE subrx.RequestId = TbServicesRequestsLog.RequestId 
                                  AND subrx.ServiceId = globrx.ServiceId
                                  ORDER BY RequestLogId DESC  LIMIT 1)"', status_code, '"');
         SET @Condition = CONCAT('GROUP BY TbServices.ServiceId ORDER BY TbServices.ServiceId ASC LIMIT 'PrRow',10')


      END IF;

      SET @Query = CONCAT(@Query, @Condition);

 PREPARE stmt FROM @Query;

 EXECUTE stmt;
 DEALLOCATE PREPARE stmt;  
END 

Answer 1

我不知道你的存储过程是什么......但固定版本是： 它有几个错误：

1. 必须将分隔符设置为默认值，因为正文将包含; ，第一行我将分隔符更改为$$

2. 连接不是自动的：

   WHERE  globrx.ProviderId = 'Prproviderid' '; 
   

   必须更改为

   concat('...
   WHERE  globrx.ProviderId = ',Prproviderid,' '); 
   

3. @condition是一个累积变量（我认为）：

   SET @Condition = CONCAT(@Condition,
   

结果是：

DELIMITER $$
DROP PROCEDURE IF EXISTS mp_test$$
CREATE PROCEDURE mp_test(
    IN PrStatus VARCHAR(255),
    IN PrStatusCode VARCHAR(255),
    IN PrProviderId VARCHAR(255),
    IN PrRow VARCHAR(255))
   BEGIN
      SET @Condition  = '';
      SET @Query = concat('   
      SELECT
      bitauth_users.fullname,
      tbservices.ServiceNameAR,
      tbservices.ServiceNameEN,
      tbservices.ServiceId,
      globrx.ProviderId,
      globrx.RequestDesc,
      TbServicesRequestsLog.status
        FROM tbservices, Tbservicesrequests globrx, 
        TbServicesRequestsLog, bitauth_users  
        WHERE  globrx.ProviderId = ',Prproviderid,' ');

    SET @Condition = '';

      IF PrStatus != '' THEN
         SET @Condition = CONCAT(@Condition,' AND globrx.RequestId = TbServicesRequestsLog.RequestId');
         SET @Condition = CONCAT(@Condition,' AND globrx.ServiceId = tbservices.ServiceId');
         SET @Condition = CONCAT(@Condition,' AND bitauth_users.user_id = globrx.ReceiverId');
         SET @Condition = CONCAT(@Condition,' AND globrx.RequestId = TbServicesRequestsLog.RequestId');
         SET @Condition = CONCAT(@Condition,' AND (SELECT status  FROM TbServicesRequestsLog,Tbservicesrequests AS subrx
                                  WHERE subrx.RequestId = TbServicesRequestsLog.RequestId 
                                  AND subrx.ServiceId = globrx.ServiceId
                                  ORDER BY RequestLogId DESC  LIMIT 1) "', status_code, '"');
         SET @Condition = CONCAT(@Condition,' GROUP BY TbServices.ServiceId ORDER BY TbServices.ServiceId ASC LIMIT ',PrRow,',10');


      END IF;

      SET @Query = CONCAT(@Query, @Condition);

    PREPARE stmt FROM @Query;

    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;  
END $$