mybatis-plus使用sum,count,distinct等函数的方法 通过mybatis-plus实现COUNT(DISTINCT user_name)的sql查询

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_info
WHERE 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);
作者:默 唁原文地址:https://blog.csdn.net/Mr_Chp/article/details/128863740

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