Function storage of MySQL high-level statements
1, Database function
1. Mathematical function
The records stored in the database often need a series of arithmetic operations, so MySQL supports many mathematical functions.
Common mathematical functions
Mathematical functiondescribeabs (x)Returns the absolute value of x; The absolute value is always positive, and the absolute value o ...
Posted by UKlee on Fri, 29 Oct 2021 06:54:35 -0700
17-09-02 (public key box *)
The liver lasted eight hours. Finally straightened out the solution of this problem, and found the biggest problem recently. It's bad, it's delicious, but it's worth it.
Self summary
1. If you can't do it, don't think about whether multiple cycles work or not. Let's talk about it first. 2. I got 30 points for the first time, but the runni ...
Posted by mezise on Fri, 29 Oct 2021 06:52:21 -0700
http module, node modularization, differences between exports and module.exports, package, npm
http module
Concept: a module used to create a web server. Through the http.createServer() method provided by the http module, you can easily turn an ordinary computer into a web server to provide web resource services
To create a Web server using the http module, you need to import it first:
const http = require('http')
Role of http module:
1 ...
Posted by scuff on Fri, 29 Oct 2021 06:48:04 -0700
MySQL full backup and recovery
introduction
With the rapid development of office automation and e-commerce, enterprises rely more and more on information system. Database, as the core of information system, plays an important role. Database backup is an important means to recover important data in time and prevent data loss in case of data loss. A reasonable database ...
Posted by Hayce on Fri, 29 Oct 2021 06:46:24 -0700
Golang reflection operation
preface
What is reflection? We often use it, and it's a rotten noun. I won't introduce it in detail here
In short, there is a variable of unknown type, its type can be obtained through reflection, and its properties and methods can be manipulated
Reflection is generally used as a generation tool method. For example, you need a ToString method t ...
Posted by Celauran on Fri, 29 Oct 2021 06:16:16 -0700
Circular statement in Java - array
Statements in Java
1. Sequential structure
2. Select structure
if statement switch Statements
3. Loop structure - repeat execution
1.for loop -- F ...
Posted by HA7E on Fri, 29 Oct 2021 05:48:30 -0700
JAVA learning 10-29 -- rewriting, super, polymorphism
Method override
1. Override: after a subclass inherits the parent class, it can override the methods in the parent class.2. Application: after rewriting, when a subclass object is created and a method with the same name and parameter in the child parent class is called through the subclass object, the method of overriding the parent class by t ...
Posted by f1nutter on Fri, 29 Oct 2021 05:34:12 -0700
Deep learning_ Perceptron
Deep learning_ Perceptron
Reference books: introduction to deep learning_ Theory and Implementation Based on python
1. Perceptron 1.1 principle: receive multiple input signals and output one signal 1.2 diagram: 1.3 diagram: the above figure shows a perceptron receiving two input signals, X1 and X2 are input signals, y are output signals ...
Posted by steveclondon on Fri, 29 Oct 2021 05:33:25 -0700
Acwing 1170. Layout (differential constraint)
Acwing 1170. Layout
meaning of the title
Cows like to stand close to their friends when waiting in line for feeding.
Farmer John has
N
N
N cows, number from
1
1
1 to
...
Posted by JayVee on Fri, 29 Oct 2021 05:15:50 -0700
Vue syntax template
1, Key modifier
1. Style binding
1.1 class binding v-bind:class="expression" Type of expression: string, array, object
1.2 style binding
v-bind:style="expression" Type of expression: string, array, object
Specific implementation:
<!DOCTYPE html>
<html>
<head>
&l ...
Posted by abhi on Fri, 29 Oct 2021 05:02:34 -0700