在开发一个列表，需要显示在当前组的预约数量，就需要对列表中每一个组编号数量统计，不想再写xml了就想

了是否在mybatis plus中有group，一查下还真有，以防后继使用，记录下来。

 QueryWrapper<MapPointMember> wrapper = new QueryWrapper<MapPointMember>();
        wrapper.groupBy("groupId");
        wrapper.in("groupId",mapPointIdList);
        wrapper.select("group_id as groupId,count(1) as count");
        List<MapPointMember> memberList = baseMapper.selectList(wrapper);
        Map<Integer,Integer> resultMap=new HashMap<Integer,Integer>();
        for (MapPointMember member:memberList) {
            resultMap.put(member.getMapPointId(),member.getMemberCount());
        }
        return resultMap;