How to select a row with MAX (column value) and DISTINCT through another column in SQL?

My desk is: id home datetime player resource ---|-----|------------|--------|--------- 1 | 10 | 04/03/2009 | john | 399 2 | 11 | 04/03/2009 | juliet | 244 5 | 12 | 04/03/2009 | borat | 555 3 | 10 | 03/03/2009 | john | 300 4 | 11 | 03/03/2009 | juliet | 200 6 | 12 | 03/03/2009 | borat | 500 7 | 13 | 24/12/2008 | b ...

Posted by elflacodepr on Sun, 22 Dec 2019 00:55:52 -0800

BeetleX's Quick Build Web Multi-room Chat Room

In fact, it is not a difficult technology to build a Web multi-room chat room. With the help of websocket s, it is easy to achieve multi-user real-time online communication interaction. Here we mainly introduce how to make this function more simple and efficient with the support of BeetleX and BeetleXjs.Next, I'll walk you through the implement ...

Posted by Azu on Sat, 21 Dec 2019 22:13:34 -0800

Summary of SpringBoot Junior Knowledge, I'm too difficult to continue...

How idea packages and publishes springboot 1.1. Environmental preparationwindow system, jdk8 environment, springboot project, maven3.5.4 environment 1.2. Package and publish Open the idea editor and open a written demo projectThen open the terminal window under the idea editor, and when you open this window, it's at the root of the directoryEn ...

Posted by trukfixer on Sat, 21 Dec 2019 19:27:51 -0800

The most detailed HashTable source parsing ever, the easiest to understand

HashTable Source Analysis For more resources and tutorials, please pay attention to the Public Number: Non-subject classes.If you think I can write, please give me a compliment. Thank you, your encouragement is the power of my creation.####1. PrefaceHashtable is an old-fashioned collection class that was born as early as JDK 1.0 ####1.1. Sum ...

Posted by adam84 on Sat, 21 Dec 2019 13:07:42 -0800

Programming STM32F0 with STM32Cube+FreeRTOS+Keil5 and sending data through USART

In the last one Sending data through USART in STM32F0 programming with STM32Cube+Keil5 Based on that, I want to use the operating system to complete the experiment of USART sending string in the task. Setting change of STM32CubeMX Enable FreeRTOS in Pinout Configure FreeRTOS in Configuration Add tasks Generate code Edit ...

Posted by frobak on Sat, 21 Dec 2019 12:58:18 -0800

Talk about rocketmq's consumemode.order

order This paper mainly studies the consumemode.order of rocketmq ConsumeMode.ORDERLY rocketmq-spring-boot-2.0.4-sources.jar!/org/apache/rocketmq/spring/annotation/ConsumeMode.java public enum ConsumeMode { /** * Receive asynchronously delivered messages concurrently */ CONCURRENTLY, /** * Receive asynchronously deli ...

Posted by hawk72500 on Sat, 21 Dec 2019 09:59:17 -0800

How to create a delegate in Objective-C?

I know how delegates work and I know how to use them. But how do I create it? #1st floor The approved answer is great, but if you're looking for a 1 minute answer, try the following: MyClass.h file should look like this (add annotated delegate line!) #import <BlaClass/BlaClass.h> @class MyClass; //define class, ...

Posted by legacyblade on Sat, 21 Dec 2019 07:14:10 -0800

Atomic issues with Java memory models

This blog series is a summary of the learning process of concurrent programming.Because there are many articles and the writing time is scattered, I organized a catalog paste (portal) for easy reference. Concurrent Programming Series Blog Portal Preface As mentioned in previous articles, JMM is a reflection of the memory model specification in ...

Posted by wilded1 on Fri, 20 Dec 2019 22:45:08 -0800

Explore the builder pattern of Java design patterns in depth

Stripping cocoons and elaborating on the structure of those things - [Sharp Lessons] Simple programs don't require a lot of design because they focus only on limited solutions and use only a few classes.Large programs focus on a wide range of designs that make more use of reusability than any other property of a good design paradigm.Ambitious i ...

Posted by vcodeinfotec on Fri, 20 Dec 2019 17:45:34 -0800

SCAU high level language programming -- Experiment 3 basic input and output

SCAU high level language programming -- Experiment 3 basic input and output 1, Exercises for upper limit of class 1. Character input and output /*Version 1*/ #include<stdio.h> int main(){ char a; scanf("%c",&a); printf("%c\n",a); return 0; } /*Version 2*/ #include<stdio.h> int main(){ cha ...

Posted by aouriques on Fri, 20 Dec 2019 07:52:44 -0800