RuoYi-Vue/ruoyi-system/src/main/resources/mapper/system/SysNoticeReadMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruoyi.system.mapper.SysNoticeReadMapper">

    <resultMap type="SysNoticeRead" id="SysNoticeReadResult">
        <id     property="readId"   column="read_id"     />
        <result property="noticeId" column="notice_id"   />
        <result property="userId"   column="user_id"     />
        <result property="readTime" column="read_time"   />
    </resultMap>

    <!-- 新增已读记录 -->
    <insert id="insertNoticeRead" parameterType="SysNoticeRead">
        insert ignore into sys_notice_read (notice_id, user_id, read_time)
        values (#{noticeId}, #{userId}, sysdate())
    </insert>

    <!-- 查询未读数量：正常状态公告 减去 当前用户已读数 -->
    <select id="selectUnreadCount" resultType="int">
        select count(*) from sys_notice n
        where n.status = '0' and not exists (select 1 from sys_notice_read r where r.notice_id = n.notice_id and r.user_id = #{userId})
    </select>

    <!-- 查询是否已读 -->
    <select id="selectIsRead" resultType="int">
        select count(*) from sys_notice_read where notice_id = #{noticeId} and user_id = #{userId}
    </select>

    <!-- 查询带已读状态的公告列表（直接在SQL中限制条数） -->
    <select id="selectNoticeListWithReadStatus" resultType="SysNotice">
        select
            n.notice_id    as noticeId,
            n.notice_title as noticeTitle,
            n.notice_type  as noticeType,
            n.status,
            n.create_by    as createBy,
            n.create_time  as createTime,
            case when r.notice_id is not null then true else false end as isRead
        from sys_notice n
        left join sys_notice_read r
            on r.notice_id = n.notice_id and r.user_id = #{userId}
        where n.status = '0'
        order by n.notice_id desc
        limit #{limit}
    </select>

    <!-- 批量标记已读 -->
    <insert id="insertNoticeReadBatch">
        insert ignore into sys_notice_read (notice_id, user_id, read_time)
        values
        <foreach collection="noticeIds" item="noticeId" separator=",">
            (#{noticeId}, #{userId}, sysdate())
        </foreach>
    </insert>

    <!-- 删除公告时清理已读记录 -->
    <delete id="deleteByNoticeIds">
        delete from sys_notice_read where notice_id in
        <foreach collection="noticeIds" item="noticeId" open="(" separator="," close=")">
            #{noticeId}
        </foreach>
    </delete>

</mapper>