api/target/classes/mapper/room/RoomBedRecordMapper.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.xjrsoft.module.room.mapper.RoomBedRecordMapper">
    <select id="getMaxSortCode" resultType="java.lang.Integer">
        SELECT IFNULL(MAX(sort_code),0) FROM room_bed_record WHERE delete_mark = 0
    </select>
</mapper>