父查询中添加临时列，以便映射到子查询中：
case when ('${sellingDate}' != '') then '${sellingDate}' else '' end as sellingDate添加临时列
<?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="cn.edu.bcu.longtermroom.hotel.pc.mybatis.mapper.RoomSellingExtendMapper">
<select id="selectRoomSellingAndDates" resultMap="BaseMap">
select id, room_id, gmt_creat,
gmt_modified, peoples, meal,
bed_type, room_type, offline,
deposit,
case when ('${sellingDate}' != '') then '${sellingDate}' else '' end as sellingDate
from room_selling
where room_id = #{roomId}
</select>
<resultMap id="BaseMap" type="cn.edu.bcu.longtermroom.hotel.pc.entity.RoomSellingExtend">
<id property="id" column="id"/>
<result property="roomId" column="room_id" />
<result property="gmtCreat" column="gmt_creat" />
<result property="gmtModified" column="gmt_modified" />
<result property="peoples" column="peoples" />
<result property="meal" column="meal" />
<result property="bedType" column="bed_type" />
<result property="roomType" column="room_type" />
<result property="offline" column="offline" />
<result property="deposit" column="deposit" />
<collection property="roomSellingDateList"
column="{id=id,sellingDate=sellingDate}"
javaType="ArrayList"
ofType="cn.edu.bcu.longtermroom.hotel.pc.entity.RoomSellingDate"
select="cn.edu.bcu.longtermroom.hotel.pc.mybatis.mapper.RoomSellingExtendMapper.selectRoomSellingDate">
</collection>
</resultMap>
<select id="selectRoomSellingDate" resultMap="BaseResult2" parameterType="java.util.Map">
select *
from room_selling_date
where room_selling_id = #{id} and selling_date like '%${sellingDate}%'
</select>
<resultMap id="BaseResult2" type="cn.edu.bcu.longtermroom.hotel.pc.entity.RoomSellingDate">
<id property="id" column="id"/>
<result property="roomSellingId" column="room_selling_id" />
<result property="sellingDate" column="selling_date" />
<result property="sellingStage" column="selling_stage" />
<result property="price" column="price" />
<result property="num" column="num" />
<result property="soldNum" column="sold_num" />
<result property="autoOff" column="auto_off" />
<result property="lastOrder" column="last_order" />
</resultMap>
</mapper>dao类型
