Mybatis 时间排序让空值NULL排在后面

有一张通知(notification)表；

需求：

1.状态(status)为发布“on”要排在未发布“off”前面；

2.先按发布时间排序再按创建时间排序，发布时间为空的要排在后面。

select * from notification;

id	content	status	create_time	publiish_time
1	aaa	on	2018-10-17 12:45:00	2018-10-17 12:45:00
2	bbb	off	2018-10-17 12:45:00
3	ccc	on	2018-10-17 12:45:00	2018-10-17 12:45:00
4	ddd	on	2018-10-17 12:45:00	2018-10-17 12:45:00
5	eee	off	2018-10-17 12:45:00

<select id="getResultList" parameterType="com.hekliu.NotificationQry" resultMap="BaseResultMap">
        SELECT
        <include refid="Base_Column_List"/>
        FROM notification
        WHERE
        1 = 1
        <if test="content != null and content !=''">
            AND content = #{content}
        </if>
        <if test="status != null and status != ''">
            AND status = #{status}
        </if>
        <if test="startPublishDate != null and startPublishDate != ''">
            AND  <![CDATA[DATE_FORMAT(publish_time,'%Y-%m-%d %H:%i:%s') >= #{startPublishDate}]]>
        </if>
        <if test="endPublishDate != null and endPublishDate != ''">
            AND <![CDATA[DATE_FORMAT(publish_time,'%Y-%m-%d %H:%i:%s') <= #{endPublishDate}]]>
        </if>
        ORDER BY
        status = "off", status = "on", create_time DESC, publish_time is NULL, publish_time DESC
    </select>

原文链接：https://blog.csdn.net/liu59412/article/details/83141566