oracle sum()over函数的使用 over不能单独使用,要和分析函数:rank(),dense_rank(),row_number()等一起使用. over函数的参数:over(partition by columnname1 order by columnname2) 含义,按columname1指定的字段进行分组排序,或者说按字段columnname1的值进行分组排序. 例如:employees表中,有两个部门的记录:department_id =10和20 select depa…
题目传送:http://acm.hdu.edu.cn/showproblem.php?pid=4704 Problem Description Sample Input 2 Sample Output 2 Hint 1. For N = 2, S(1) = S(2) = 1. 2. The input file consists of multiple test cases. 题意是输入一个N,求N被分成1个数的结果+被分成2个数的结果+...+被分成N个数的结果,N很大 1.隔板原…
[抄题]: Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. The update(i, val) function modifies nums by updating the element at index i to val. Example: Given nums = [1, 3, 5] sumRange(0, 2) -> 9 updat…