第一种

1 <if test="AGTNAM !=null and AGTNAM !=''">

       <![CDATA[and AGTNAM like concat(concat('%',#{AGTNAM}),'%'))]]>

 </if>

第二种 
1 <select id="selectUserByName" parameterType="string" resultType="user">

        select * from user where username like '%${value}%'

 </select>
备注：${}可以接收简单类型值或pojo属性值，如果parameterType传输单个简单类型值，${}括号中只能是value，使用${}不能防止sql注入，但是有时用${}会非常方便

insert into mytest_t values(1,'张三',to_date('2011-09-09','yyyy-MM-dd'))

insert into mytest_t values(1,'张三',to_date('20110909','yyyyMMdd'))

insert into mytest_t values(1,'zhangdan','2011-09-09')

日期输出的格式是由 to_char 决定的
select to_char(to_date(birthday01,'yyyy-mm-dd'),'yyyy-MM-dd') from MYTEST_T     输出是：yyyy-MM-dd
select to_char(to_date(birthday01,'yyyy-mm-dd'),'yyyyMMdd') from MYTEST_T       输出是：yyyyMMdd

select to_char(birthday,'yyyy-MM-dd') from MYTEST_T             格式 是由to_char 决定的

select to_char(birthday,'yyyyMMdd') from MYTEST_T 

select to_char(sysdate,'yyyy-MM-dd hh24:mi:ss') as nowTime from dual;   //日期转化为字符串

select to_char(sysdate,'yyyy')  as myyear   from mytest;   //获取时间的年

select to_char(sysdate,'mm')    as myMonth  from mytest;   //获取时间的月

select to_char(sysdate,'dd')    as myDay    from mytest;   //获取时间的日

select to_char(sysdate,'hh24')  as myHour   from mytest;   //获取时间的时

select to_char(sysdate,'mi')    as myMinute from mytest;   //获取时间的分

select to_char(sysdate,'ss')    as mySecond from mytest;   //获取时间的秒