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写法一：

XML

   
     BEGIN 
    
      UPDATE v_cqms_qcsample c SET CQMS_FLAG = '1' where 'XN_' || ID = #{item.ID,jdbcType = VARCHAR} 
     ;END; 
   

service部分代码：

long t1 = System.currentTimeMillis();qcsampleMapper.updateFlagList(qcsampleList);long t2 = System.currentTimeMillis();System.out.println(t2-t1);

执行结果：59645

这种写法的形式是把所有的sql写好后，一起提交给数据库去执行，实际也是一个个子sql更新语句。

方法二

XML：

   
                UPDATE v_cqms_qcsample c            SET CQMS_FLAG = '1'            WHERE        
    
                 ('XN_' || ID = (#{item.ID,jdbcType = VARCHAR}))        
     
   

后台打印的sql语句：

UPDATE v_cqms_qcsample c SET CQMS_FLAG = '1' WHERE ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?)) or ('XN_' || ID = (?))

执行结果（同样的49条语句）：35681

总的说来，后面执行一条sql语句的效率远高于多条sql语句的执行。还有需要说明的是，这里只是简单的执行啦两种情况，并没有去深究底层原理。为了更灵活的使用mybatis,建议去仔细学习了解mybatis标签，相信会对数据库的操作更得心应手。

我是简单，一个爱学习，爱分享的精神小伙。

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