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

通过mybatis-plus实现以下sql查询

SELECT COUNT(DISTINCT user_name)FROM user_infoWHERE is_deleted=0 AND is_enabled = 1

mybatis-plus实现

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

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

QueryWrapper wrapper1 = new QueryWrapper<>();        wrapper1.select("count(user_id) as userids",                "sum(age) as ages")                .in("user_id","1,2,3");Map 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);

来源地址：https://blog.csdn.net/Mr_Chp/article/details/128863740