java-insagent-pc/target/classes/mapper/modules/message/MessageSecretaryMapper.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.ydtech.modules.message.dao.MessageSecretaryMapper">

    <select id="getUserMessageList" resultType="com.ydtech.modules.message.entity.MessageSecretary">
        SELECT id, msg_type, from_user, to_user, content, status, create_time, read_time
        FROM (
                 SELECT id, msg_type, from_user, to_user, content, status, create_time, read_time,
                        ROW_NUMBER() OVER (PARTITION BY msg_type ORDER BY create_time DESC) as rn
                 FROM message_secretary
                 WHERE to_user = #{userId}
             ) AS temp
        WHERE rn = 1;
    </select>

</mapper>