oracle分页语句

<select id="queryDefinedUserGroup" parameterType="java.util.Map"
		resultType="com.huawei.iop.bean.TaskInfo">
		select c.* from(
		select t.*,rownum rm from(
		select
		groupID,
		groupName,
		groupDescribe,
		status,
		userNum,
		downloadPath,
		from
		DIM_WORLDCUP_DEFINED_TASK
		where 1=1
		<if test="groupName != null and groupName != ''">
			and groupName = #{groupName}
		</if>
		)t
		where rownum &lt;= #{end}) c
		where rm &gt;= #{start}
	</select>