Mysql游标中拼接sql字符串执行

CREATE DEFINER=`mycommcrm`@`%` PROCEDURE `insert_source_flag`(IN `tableName` varchar(60))
BEGIN

#原始欠费数据    暂依据 客户唯一标记,起始账期,结束账期,账务月份区分
  declarev_start_time  datetime DEFAULT now();
  declare startAccountDate	varchar(64);     -- 起始账期 
  declare endAccountDate	varchar(64);         -- 结束账期 
  declare accountMonth	varchar(64);	     -- 账务月份
  declare onlyFlag int;
  declarea int DEFAULT 0;

-- 遍历数据结束标志
  declare ifEnd int  DEFAULT false;
 -- 声明游标
  DECLARE cti_dialout_temp_curs cursor for ( 
          select start_account_date,end_account_date,account_month,only_flag from cti_dialout_temp       
       );  

  -- 将结束标志绑定到游标
	 declare CONTINUE HANDLER FOR not found SET ifEnd = true;
	 
-- 打开游标	
open cti_dialout_temp_curs;

-- 循环遍历
read_loop: LOOP

	-- 提取变量值
    fetch cti_dialout_temp_curs into startAccountDate,endAccountDate,accountMonth,onlyFlag;
    
     -- 判断是否退出循环
	  IF ifEnd THEN
       LEAVE read_loop;
      END IF;
   
    ---  凭借sql
    # 如果该条数据不存在于上月初始欠费表,则加上初始欠费标记.  依据条件: 开始账期,结束账期,账务月份,唯一标记
	  set @exesql = CONCAT('select count(1) into @count from ',tableName ,' where start_account_date= ',startAccountDate);
	  set @exesql = CONCAT(@exesql,' AND end_account_date= ',endAccountDate,' AND account_month= ',accountMonth);
	  set @exesql = CONCAT(@exesql,' AND only_flag= ',onlyFlag);

	  prepare stmt from @exesql;
	  execute stmt;
	  DEALLOCATE prepare stmt;


    if @count<1 THEN
		    	update 
		    			cti_dialout_temp 
		    	 set    source_flag= 1
				where       start_account_date=startAccountDate 
					AND     end_account_date=endAccountDate
       			    AND     account_month=accountMonth
       			    AND     only_flag=onlyFlag;		
    end if;
	

    set @count = 0;


 -- 关闭循环
end Loop;

-- 关闭游标
close cti_dialout_temp_curs;


   #加入本月的初始欠费数据 
   set @exesql = CONCAT('INSERT INTO  ',tableName ,'  select * from cti_dialout_temp a  where a.source_flag =1');
   prepare stmt from @exesql;
   execute stmt;
   DEALLOCATE prepare stmt;

	 SELECT concat('耗时：', unix_timestamp(now()) - unix_timestamp(v_start_time), '秒!');

END