<?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.project.benyi.mapper.ByDatetimeMapper">

    <resultMap type="ByDatetime" id="ByDatetimeResult">
        <result property="day" column="day"/>
        <result property="sort" column="sort"/>
        <result property="dayscount" column="dayscount"/>
        <result property="month" column="month"/>
    </resultMap>


    <select id="selectByDatetimeList" parameterType="ByDatetime" resultMap="ByDatetimeResult">
        select CONCAT(#{month},'-',help_topic_id +1) day,help_topic_id as sort,day(last_day( CONCAT(#{month},'-1')))
        as dayscount
        from mysql.help_topic
        where help_topic_id &lt; day(last_day(CONCAT(#{month},'-1')))
        order by help_topic_id
    </select>

</mapper>