【SQL学习笔记八索引,表连接,子查询,ROW_NUMBER】教程文章相关的互联网学习教程文章

Excel Sheet Column Number【代码】【图】

这道题可以看作是26进制问题。26进制就是最多可以用26个不同的符号组合在一起来表示一个数值。因此,ABC代表的数值就是:A*262+B*261+C*260=1*262+2*261+3*260,其他字母组合以此类推。下面这种方法是一种很直观的思路,但是要调用C++库函数pow(x,a),计算时间会变长。pow(x,a)可以求得x的a次幂,‘A‘的ASCII码是64。class Solution { public:int titleToNumber(string s) {int n=s.size()-1;int result=0;for(int i=0;i<=n;i++){...

Single Number II【代码】【图】

Question:Given an array of integers, every element appears three times except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?Solution: 1class Solution {2public:3int singleNumber(vector<int>& nums) {4 sort(nums.begin(),nums.end());5for(int i=0;i<nums.size();i+=3)6 {7if(nums[i]!=nums[i+1])8 {9r...

HDU 1005 Number Sequence【代码】

HDU-1005题解:每次的数都会对7进行mod操作,mod之后数的范围一定在[0,6]之间,如果每次都循环到n的话明显会TLE,那么就说明这个结果会出现一个周期,我们只要找到这个周期,然后根据周期进行mod,然后找到结果就好了。PS:讨论区的最简代码的mod48操作我也不是很理解,但是有人是说错的,hdu数据水而已,2333。(反正我觉得找周期靠谱)代码: 1 #include<iostream>2usingnamespace std;3constint N = 7;4longlong A, B, n,f1,f2,f...

SQL的ROW_NUMBER函数

tabs as ( select ROW_NUMBER() over(partition by customerID order by totalPrice) as rows,customerID,totalPrice, DID from OP_Order ) select MAX(rows) as ‘下单次数‘,customerID from tabs group by customerID with tabs as ( select ROW_NUMBER() over(partition by customerID order by insDT) as rows,customerID,totalPrice, DID from OP_Order ) select * from tabs where totalPrice in ( s...

Source insight 3572安装和版本号An invalid source insight serial number was detected解【图】

Source insight最新版本3572下载链接:http://www.sourceinsight.com/down35.html, http://www.sourceinsight.com/distribute/Si3570Setup.exe注冊号:SI3US-205035-364481.卸载掉旧版安装新版, 可能会有提示" An invalid source insight serial number was detected",然后不能使用.解决方法:(1) 快捷键:WIN+R,或者 開始 -> 附件 -> 执行,输入regedit,打开注冊表编辑器(2) 找到source insight 的安装路径32位系统路径例如以下:64位...

[LeetCode]Letter Combinations of a Phone Number【代码】

Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below.Input:Digit string "23" Output: ["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"]. Note: Although the above answer is in lexicographical order, your answer could be in any order you want. 采用两种方式都可以实现DFS和BFS...

HDOJ 1005 Number Sequence【代码】【图】

Problem DescriptionA number sequence is defined as follows:f(1) = 1, f(2) = 1, f(n) = (A * f(n - 1) + B * f(n - 2)) mod 7.Given A, B, and n, you are to calculate the value of f(n). InputThe input consists of multiple test cases. Each test case contains 3 integers A, B and n on a single line (1 <= A, B <= 1000, 1 <= n <= 100,000,000). Three zeros signal the end of input and this test case is ...

详述 SQL 中的 distinct 和 row_number() over() 的区别及用法【代码】【图】

DISTINCT 列名称 FROM 表名称假设有一个表“CESHIDEMO”,包含两个字段,分别 NAME 和 AGE,具体格式如下:观察以上的表,咱们会发现:拥有相同 NAME 的记录有两条,拥有相同 AGE 的记录有三条。如果咱们运行下面这条 SQL 语句,/** * 其中 PPPRDER 为 Schema 的名字,即表 CESHIDEMO 在 PPPRDER 中 */select name from PPPRDER.CESHIDEMO将会得到如下结果:观察该结果,咱们会发现在以上的四条记录中,包含两条 NAME 值相同的记录...

1074. Number of Submatrices That Sum to Target (H)【代码】【图】

Number of Submatrices That Sum to Target (H) 题目 Given a matrix and a target, return the number of non-empty submatrices that sum to target. A submatrix x1, y1, x2, y2 is the set of all cells matrix[x][y] with x1 <= x <= x2 and y1 <= y <= y2. Two submatrices (x1, y1, x2, y2) and (x1', y1', x2', y2') are different if they have some coordinate that is different: for example, if x1 != x1'. Example 1...

Leetcode 202: Happy Number【代码】

问题描述: Write an algorithm to determine if a number n is happy. A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits. Repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are...

SQL学习笔记八索引,表连接,子查询,ROW_NUMBER

索引 经常要查询的语句,则给它建一个索引 表连接 select T_Oders as o join T_Customers as C on o.CustomerId = c.Id 子查询 单值子查询 单列多值子查询 ROW_NUMBER()函数 ROW_NUMBER() OVER(ORDER BY Fsalary DESC) 您可能感兴趣的文章:使用SQL Server数据库嵌套子查询的方法常用SQL语句(嵌套子查询/随机等等)详细整理SQL Server高级内容之子查询和表链接概述及使用详细讲述MySQL中的子查询操作浅谈MySQL中的子查询优化技巧对My...

SQL查询以查找表中min_numbers和max_number之间的孔【代码】

SQL专家的快速提问. 我有一个表,其中包含两列-min_number和max_number我一直在尝试写一个查询,但未成功找到最小和最大数字之间的第n个孔 例min max 1. 100 200 2. 250 300 3. 330 400如果我想找到一个大小为50的孔,则将返回第1行的最大值200(在第2行的最小值和第2行的最小值之间有50的孔),第20行的孔将返回第2s的最大值300,以此类推.如果不存在合适大小的孔,则将返回最后的最大值(400). 谢谢解决方法:编辑:最终...

sql 两种分页offset和row_number简单分析【图】

(‘tempdb..#test‘) is not null drop table #test create table #test(id int)insert into #test(id)values(1),(2),(3),(4),(5),(6) declare @page int---当前页面declare @rows int---页面大小set @page=2set @rows=3 ---------当前页面为2,页面大小为3---则结果得到id(4,5,6)-------- (1)使用offset i rows fetch next j rows only 方式---i=(@page-1)*@rows,j=@rowsselect t10.id from #test t10order by t10.id--需要一个...

代码杂谈-SQL中的rank&row_number函数

两个函数细节记不住. 写个例子备注一下.select no, name, score , rank() over(partition by no order by score asc) rk1 , rank() over(partition by no order by score desc) rk2 , row_number() over(partition by no order by score asc) rn1 , row_number() over(partition by no order by score desc) rn2from values (1,'a',1), (1,'a', null),(1, 'b',2), (1, 'b',-2), (1, 'b',1)t (no, name, score) ; 结果no name sco...

<LeetCode OJ> 200. Number of Islands【代码】

Total Accepted: 48411 TotalSubmissions: 171609 Difficulty: MediumGiven a 2d grid map of ‘1‘s(land) and ‘0‘s (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.Example 1:11110110101100000000Answer: 1Example 2:11000110000010000011Answer:...