0 SELECT basics
Displays the population of Germany
SELECT population FROM world
WHERE name = 'Germany '
A country with an area of more than 5000000 square kilometers displays its name and per capita GDP for each country
SELECT name, GDP/population FROM world
WHERE area > 5000000
Displays the country name and population of &quo ...
Posted by runawaykinms on Sun, 08 May 2022 22:06:06 +0300
Advanced 2: condition query
Take the following database as an example to write a conditional query case
1, Filter by conditional expression
Simple conditional operator:> < = != <> >= <=
2, Filter by logical expression ...
Posted by hammerslane on Sun, 08 May 2022 13:49:34 +0300
Author: Yao yuan
Focus on Oracle and MySQL databases for many years, Oracle 10G and 12C OCM, MySQL 5.6, 5.7, 8.0 OCP. Now Dingjia technology serves as a technical consultant to provide database training and technical support services for colleagues and customers.
Source of this article: original contribution * produced by aikesheng o ...
Posted by squalls_dreams on Sun, 08 May 2022 03:53:20 +0300
029 SQL basic query and data update
– workbench: Software
– query data: select //Query the name of fruit with a price of 10.2 yuan from the fruits table
select f_name(,f_price Better look) from fruits where f_price=10.2;
– query with in keyword: discrete value //Query s from the fruits table_ Records with IDS 101 an ...
Posted by spamyboy on Sat, 07 May 2022 23:01:58 +0300
1. Preliminary preparation:
Download centeos 7.5: https://mirrors.aliyun.com/centos-vault/7.5.1804/isos/x86_64/
Download floppy disk pass, the registration code is Baidu.
download putty, winscp
2. Operation steps:
u disk production:
Open UltraISO tool File -> Open Select your ISO file.
Startup item Select to write the hard disk image ...
Posted by AliceG on Sat, 07 May 2022 16:36:06 +0300
Introduction to Shiro Security Framework
Overview of Shiro
Shiro is an open source security framework under apache ( http://shiro.apache.org/) It extracts the functions related to the security authentication of the software system, realizes the functions of user identity authentication, authority authorization, encryption, session management, e ...
Posted by battlesiege on Sat, 07 May 2022 05:13:50 +0300
When closing mysql server, various problems may occur due to the closing method. The following steps can reduce the occurrence of problems.
1. Stop copying
In some special environments, the slave node may try to start from the wrong position. In order to reduce this risk, stop io thread first, so as not to receive new event information.
Posted by richcrack on Sat, 07 May 2022 01:14:22 +0300
Overview of MHA cluster
Introduction to MHA
MHA(Master high Availability)
It is developed by DeNA company in Japan. It is an excellent solution to realize high availability of MySQL. The automatic failover operation of the database can be completed within 0 ~ 30 seconds. MHA can ensure the consistency of data to the ...
Posted by eva21 on Thu, 05 May 2022 22:26:27 +0300
SSM (Spring + spring MVC + MyBatis) framework set is integrated by spring and MyBatis (spring MVC is part of spring), which is often used as the framework of web projects with simple data source.
1, Create a web project based on maven Management:
1.1 complete the project structure ...
Posted by xxreenaxx1 on Thu, 05 May 2022 12:34:15 +0300