(ROWS | RANGE) BETWEEN CURRENT ROW AND (CURRENT ROW | (UNBOUNDED | [num]) FOLLOWING) 区别 ROWS BETWEEN 3 PRECEDING AND 4 FOLLOWING:表示在当前顺序的前提下,往前3行数据和往后4行数据,总计8行,当然这个8行不是绝对的,比如排序后的第一条数据亦或排序后的最后一条数据,
比如rows between 1 preceding and 1 following代表从当前行往前一行以及往后一行。 range between … and … range:指以当前行在开窗函数中的值为根基,然后按照order by进行排序,最后根据range去加减上下界。是逻辑意义上的行。 比如sum(score) over (PARTITION by id order by score RANGE BETWEEN 1 PRECEDING A...
在Hive SQL中,RANGE BETWEEN 是一个用于窗口函数的子句,它允许你指定一个范围,用于计算窗口函数的结果。下面是对 RANGE BETWEEN 的详细解释:1. RANGE BETWEEN 的用法 RANGE BETWEEN 用于定义窗口函数的计算范围。它可以根据当前行的值以及指定的范围来确定窗口的起始和结束行。这通常用于进行累计、移动平均等计算。
注意: last_value默认的窗口是RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW,表示当前行永远是最后一个值,需改成RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING。 RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW 为默认值,即当指定了ORDER BY从句,而省略了window从句 ,表示从开始到当前行。 RANGE ...
range格式1: 如果当前值在80,取值就会落在范围在80-2=78和80+2=82组件之内的行 max(score) over (partition by clazz order by score desc range between 2 PRECEDING and 2 FOLLOWING) hive> select *,sum(score) over (partition by clazz order by score desc rows between 2 preceding and 2 following...
答案马上揭晓:标准聚合函数作为窗口函数使用的时候,在指明order by的情况下,如果没有Window子句,则Window子句默认为:RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW(上边界不限制,下边界到当前行)。 移动计算 移动计算是在分区和排序的基础上,对计算范围进一步做出限定。
-- sql ② select id, dept, salary, min(salary) over(partition by dept order by id) min_sal from dept; 上⾯①②中的min_salary字段的值会不⼀样,原因是②中使⽤order by后,等同于 min(salary) over(partition by dept order by userid range between unbounded preceding and current row )...
另一种是使用 RANGE 子句,按照排列序列的当前值,根据相同值来确定分区中的行数。 语法: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 ORDERBY字段名RANGE|ROWS边界规则0|[BETWEEN边界规则1AND边界规则2] RANGE | ROWS的区别是什么? RANGE表示按照值的范围进行范围的定义,而ROWS表示按照行的范围进行范围的...
还有一种方式是RANGE BETWEEN 这种就是以当前值为锚点进行计算。比如RANGE BETWEEN 20 PRECEDING AND 10 FOLLOWING当前值为50的话就去前后的值在30到60之间的数据。 2.3 window Function 实现原理 窗口函数的实现,主要借助 Partitioned Table Function (即PTF); ...
窗口子句，可以进一步限定范围(rows | range) between (unbounded | [num]) preceding and ([num] preceding | current row | (unbounded | [num]) following(rows | range) between current row and (current row | (unbounded | [num]) following)(rows | range) between [num] following and (unbounded...