ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW是Oracle窗口函数(Window Function)中的一个子句,用于指定窗口的范围。这个子句的意思是,窗口从分组(或整个查询结果集,如果没有使用PARTITION BY子句的话)的第一行开始,到当前行为止。这种窗口定义方式常用于计算累积值(如累积和、累积平均值等)或滚动统计。
1.“rows between unbounded preceding and current row” 功能可实现与lead类似功能,但使用较为复杂,没lead好理解; 2.“rows between unbounded preceding and current row”与lead不同之处在于lead最后一条数据为NULL; 3.“rows between unbounded preceding and current row”、lead、以及IoT数仓中delta函数均可实...
首先我们来看 :rows between 1 preceding and 1 following 告诉 Oracle 在当前记录的前一条、后一条范围内查找并统计,而 first_value 和 last_value 在这 3 条记录中至分别找出第一条、第三条记录,这样我们就轻松地得到相邻三个月的销售记录及平均值了! 六、窗口函数进阶-比较相邻记录: 通过第五部分的学习,...
首先我们来看 :rows between 1 preceding and 1 following 告诉 Oracle 在当前记录的前一条、后一条范围内查找并统计,而 first_value 和 last_value 在这 3 条记录中至分别找出第一条、第三条记录,这样我们就轻松地得到相邻三个月的销售记录及平均值了! 六、窗口函数进阶-比较相邻 记录: 通过第五部分的学习...
(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,根据行数判定肯定不会是8行。
●ROWS BETWEEN 1 PRECEDING AND CURRENT ROW :指当前行的上一行(ROWNUM-1)到当前行的数据 ●ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING :指当前行的上一行(ROWNUM-1)到当前行的下一行(ROWNUM+1)的数据 ●RANGE BETWEEN CURRENT ROW AND 350 FOLLOWING:指当前行到当前行数据+350的范围内的数据 ●RANGE BETWEEN...
CURRENT ROW:当前行 UNBOUNDED:起点(一般结合PRECEDING,FOLLOWING使用) UNBOUNDED PRECEDING 表示该窗口最前面的行(起点) UNBOUNDED FOLLOWING:表示该窗口最后面的行(终点) 比如说: ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW(表示从起点到当前行) ROWS BETWEEN 2 PRECEDING AND 1 FOLLOWING(表示往前2行到往后1行...
Oracle开发之:窗口函数 (转) rows between unbounded preceding and current row 2016-11-09 17:05 −... EchoLong333 1 10250 Difference Between Currency Swap and FX Swap 2019-12-24 13:52 −[z]https://www.differencebetween.com/difference-between-currency-swap-and-vs-fx-swap/ Currency Swap ...
rows between unbounded preceding and current row rows between current row and unbounded following rows between unbounded preceding and unbounded following 输出被省略 - 与上方相同 然而,ROWS允许更多的控制,因为您也可以执行上面的语法,而这在使用RANGE时会失败: ...
LAST_VALUE(salary) OVER (PARTITION BY dep ORDER BY salary row BETWEEN UNBOUNDED PRECEDING AND current row) as t2 from emp; [开窗子句] 默认时行开窗,前导无界到当前行。 row BETWEEN UNBOUNDED PRECEDING AND current row) //行开窗 row BETWEEN UNBOUNDED PRECEDING AND unbounded folloing //行开窗 ...