一、根据日期按天分组查询倒序

//mapper
public List<Date> dateByPatientId(FollowScheme followScheme);

<select id="dateByPatientId" parameterType="com.ruoyi.follow.domain.FollowScheme" resultType="java.util.Date">
        SELECT DATE(create_time) as create_time FROM follow_scheme
        WHERE platform_id = #{platformId} AND patient_id = #{patientId}
        GROUP BY DATE(create_time)
        ORDER BY MAX(create_time) DESC;
    </select>

总结：

• 查询结果为日期集合，java用List<Date>接收，MyBatis配置resultType="java.util.Date"
• 库中的create_time有具体的时分秒，按天分组转化函数DATE(create_time)
• 分组按日期倒序，最新的日期放在最上面ORDER BY MAX(create_time) DESC

二、查询指定日期的记录

<select id="listByPatientId" parameterType="com.ruoyi.follow.domain.FollowScheme" resultMap="FollowSchemeResult">
        <include refid="selectFollowSchemeVo"/>
        where platform_id = #{platformId} AND patient_id = #{patientId} AND DATE(create_time) = #{createTime}
    </select>

总结：

• 传进来的参数是天，条件DATE(create_time) = #{createTime}