Hive 开窗函数

week

发布于 2020-03-25 17:32:13

7020

普通的聚合函数聚合的行集是组,开窗函数聚合的行集是窗口。因此,普通的聚合函数每组(Group by)只返回一个值，而开窗函数则可为窗口中的每行都返回一个值。简单理解，就是对查询的结果多出一列，这一列可以是聚合值，也可以是排序值。开窗函数一般分为两类,聚合开窗函数和排序开窗函数。

-- 建表
create table student_scores(
id int,
studentId int,
language int,
math int,
english int,
classId string,
departmentId string
);
-- 写入数据
insert into table student_scores values 
  (1,111,68,69,90,'class1','department1'),
  (2,112,73,80,96,'class1','department1'),
  (3,113,90,74,75,'class1','department1'),
  (4,114,89,94,93,'class1','department1'),
  (5,115,99,93,89,'class1','department1'),
  (6,121,96,74,79,'class2','department1'),
  (7,122,89,86,85,'class2','department1'),
  (8,123,70,78,61,'class2','department1'),
  (9,124,76,70,76,'class2','department1'),
  (10,211,89,93,60,'class1','department2'),
  (11,212,76,83,75,'class1','department2'),
  (12,213,71,94,90,'class1','department2'),
  (13,214,94,94,66,'class1','department2'),
  (14,215,84,82,73,'class1','department2'),
  (15,216,85,74,93,'class1',

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原始发表：2020/03/24 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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