二十六画生的博客

Hive cross join ，结果是笛卡尔积，不能写on字段,1 2 on报错 3 t2 cross join t1 end...

正数的补码与原码一致，负数的补码与原码不同，Java中的<< / >>/>>>均是对补码操作（java中存储的也只是补码），如果补码是负数，需要再转换为原码才是真实的负数值...

0 源表 1 报错，因为没有通过聚合或别名或常量生成新的字段.【5正确】 2 正确 3 正确 4 正确 5 正确...

转换成： 方法1: sum(case when...) 2 方法2: sum(map['']) 方法1不带sum的结果，与方法2不带sum的结果 相同，如下：...

select --case --when month = '01' THEN sum_qty --end as '01', --SqlParseException: Sql...

select concat_ws(',', 1, 2, null, 3), --1,2,3 concat_ws(1, 2, null,...

Given the head of a singly linked list, reverse the list, and return the reversed list...

一起养成写作习惯！这是我参与「掘金日新计划 · 4 月更文挑战」的第13天，点击查看活动详情。 Given an array of n integers nums and ...

Write an efficient algorithm that searches for a value target in an m x n integer matr...

Design a data structure that follows the constraints of a Least Recently Used (LRU) ca...

Given the head of a sorted linked list, delete all duplicates such that each element a...

Given the head of a sorted linked list, delete all nodes that have duplicate numbers, ...

Given the head of a singly linked list, return true if it is a palindrome. Example 1: ...

Write a function to delete a node in a singly-linked list. You will not be given acces...

一起养成写作习惯！这是我参与「掘金日新计划 · 4 月更文挑战」的第6天，点击查看活动详情。 You are given a perfect binary tree whe...

一起养成写作习惯！这是我参与「掘金日新计划 · 4 月更文挑战」的第5天，点击查看活动详情。 Given the head of a singly linked list,...

Given a string columnTitle that represents the column title as appear in an Excel shee...

一起养成写作习惯！这是我参与「掘金日新计划 · 4 月更文挑战」的第3天，点击查看活动详情。 Given two strings s and t, return true ...

Given an integer n, return a string array answer (1-indexed) where : answer[i] == "Fiz...