BEGIN

     #Routine body goes here...

   /*SQL语句变量*/

   DECLARE vstrSql VARCHAR(3000) DEFAULT '';

   /*映射表字段*/

   DECLARE vSourceTableName VARCHAR(50);

   DECLARE vSourceIdFieldName VARCHAR(50);

   DECLARE vSourceNameFieldName VARCHAR(50);

   DECLARE vTargetTableName VARCHAR(50);

   DECLARE vTargetIdFieldName VARCHAR(50);

   DECLARE vTargetNameFieldName VARCHAR(50); 

   /*更新数据*/

   DECLARE vnewValue VARCHAR(100);

   DECLARE vSourceIdFieldValue VARCHAR(100);

   DECLARE Done INT DEFAULT 0;

   /*声明游标*/

   DECLARE curRow CURSOR FOR

   SELECT SourceTableName,SourceIdFieldName,SourceNameFieldName,TargetTableName,TargetIdFieldName,TargetNameFieldName

   FROM db_redundancy.TableFieldMap;

   /*设置终止标记*/

   DECLARE CONTINUE HANDLER FOR SQLSTATE '' SET Done = 1;

   /*打开游标*/

   OPEN curRow;

     /*循环取出数据*/

     FETCH NEXT FROM curRow INTO vSourceTableName,vSourceIdFieldName,vSourceNameFieldName,vTargetTableName,vTargetIdFieldName,vTargetNameFieldName;

     WHILE Done<>1 DO

        #获取需要更新的数据

        SELECT SourceNameFieldNewValue,SourceIdFieldValue INTO vnewValue,vSourceIdFieldValue FROM db_redundancy.TableFieldValueModifyLog

        WHERE  IsProcess=0 AND SourceTableName=vSourceTableName AND SourceIdFieldName=vSourceIdFieldName AND SourceNameFieldName=vSourceNameFieldName

        ORDER BY CreateDate DESC  limit 1;

        IF ISNULL(vnewValue) <> NULL || LENGTH(trim(vnewValue))>1 THEN

          #拼接语句

          SET vstrSql=CONCAT(' UPDATE ',vTargetTableName,' SET ', vTargetNameFieldName ,' = "',vnewValue,'" WHERE ', vTargetIdFieldName ,' = ', vSourceIdFieldValue,';');

          #注意很重要，将连成成的字符串赋值给一个变量（可以之前没有定义，但要以@开头）

          SET @vSql= vstrSql;

          #预处理需要执行的动态SQL，其中stmt是一个变量

          PREPARE stmt  FROM @vSql;

          #执行语句

          EXECUTE stmt ;

          #释放语句

          DEALLOCATE PREPARE  stmt;

          #更新历史表中状态标记

          UPDATE db_redundancy.TableFieldValueModifyLog SET IsProcess=1 WHERE IsProcess=0 AND SourceTableName=vSourceTableName AND SourceIdFieldName=vSourceIdFieldName AND SourceIdFieldValue=vSourceIdFieldValue;

        END IF;

        #重置数据

        SET vnewValue='';

        SET vstrSql='';

       FETCH NEXT FROM curRow INTO vSourceTableName,vSourceIdFieldName,vSourceNameFieldName,vTargetTableName,vTargetIdFieldName,vTargetNameFieldName;

     END WHILE;

   /*关闭游标*/

   CLOSE curRow;

 END