activiti中的查询sql

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">

<mapper namespace="com.le.ssm.dao.flow.FlowTaskMapper">

    <!-- 参数映射 -->
    <resultMap id="TaskRM" type="com.le.ssm.domain.flow.Task">
        <id property="id" column="id_" javaType="String" jdbcType="VARCHAR"/>
        <result property="startTime" column="start_time_" javaType="Date" jdbcType="TIMESTAMP"/>
        <result property="endTime" column="end_time_" javaType="Date" jdbcType="TIMESTAMP"/>
        <result property="status" column="status" javaType="String" jdbcType="CHAR"/>
    </resultMap>

    <!--
        分页查询指定人的任务
        status: 1:待签收 2:已经签收3:历史任务
    -->
    <sql id="getAllTaskSQL">
        <!-- 查询待签收  -->
        select
            art.id_,
            art.create_time_ start_time_,
            null as end_time_,
            "1" as `status`
        from
            act_ru_task art
            left join act_ru_identitylink ari on art.id_ = ari.task_id_
        where
            art.assignee_ is null
            and (
                ( ari.user_id_ = #{userId} )
                or (
                    ari.group_id_ in (
                    select
                        aig.id_
                    from
                        act_id_user aiu
                        inner join act_id_membership aim on aiu.id_ = #{userId}
                        and aiu.id_ = aim.user_id_
                        inner join act_id_group aig on aig.id_ = aim.group_id_
                    )
                )
            ) 

        union all
        <!-- 查询已签收  -->
        select
            art.id_,
            art.create_time_ start_time_,
            null as end_time_,
            "2" as `status`
        from
            act_ru_task art
        where
            art.assignee_ = #{userId} 

        union all
        <!-- 查询已完成 -->
        select
            aht.id_,
            aht.start_time_,
            aht.end_time_,
            "3" as `status`
        from
            act_hi_taskinst aht
        where
            aht.assignee_ = #{userId}
    </sql>

    <select id="getAllTask" resultMap="TaskRM">
        select
            tab.id_,
            tab.start_time_,
            tab.end_time_,
            tab.`status`
        from
            (<include refid="getAllTaskSQL" />) tab
        order by tab.start_time_ desc
        limit #{pageNum}, #{pageSize}
    </select>

    <select id="getAllTaskCount" resultMap="TaskRM">
        select
            count(1)
        from
            (<include refid="getAllTaskSQL" />) tab
    </select>
</mapper>