mybatis-plus使用sum,count,distinct等函数的方法

mybatis-plus使用sum,count,distinct等函数的方法

通过mybatis-plus实现以下sql查询

SELECTCOUNT(DISTINCT user_name)FROM user_info
WHERE is_deleted=0AND is_enabled =1

mybatis-plus实现

int count =this.count(Wrappers.<User>query().select("DISTINCT user_name").lambda().eq(User::getIsEnabled,1));//或者int count1 =this.count(Wrappers.<User>query().select("DISTINCT user_name").eq("is_enabled",1));

QueryWrapper<User> wrapper1 =newQueryWrapper<>();
        wrapper1.select("distinct user_id,user_name ").in("user_id","1,2,3");List<User> list1 =this.list(wrapper1);

QueryWrapper<User> wrapper1 =newQueryWrapper<>();
        wrapper1.select("count(user_id) as userids","sum(age) as ages").in("user_id","1,2,3");Map<String,Object> map =this.getMap(wrapper1);
map.get("userids");//也可以将map转换为实体类，只不过字段需要对应JSON.parseObject(JSON.toJSONString(map),ScoreData.class);