Programmer Think

MySQL tables and data types I View database version select version(); II Database operation 2.1. Create database create database if not exists test_db default charset utf8 collate utf8_general_ci; The meaning of this SQL is: create if the database does not exist, do not create if it exists, and create test_db database, and set the char ...

1, PHP development landing page 1. Database construction First create a test database login table in mysql database: Set the following fields: id: it is unique, type int, and select the primary key. uesrname: user name, type varchar, length 30. Password: password, type varchar, length 30. Add a user name and password for testing A d ...

1, Computer purpose 1. Master functions and user-defined functions; 2. Master the storage process; 3. Master trigger; 4. Master events; 5. Master preprocessing statements. 2, Computer content (1) Create a user-defined function named MyFun without parameters. The function is to query the course name of C3 from data table C and call the f ...

Application and syntax rules of MySQL sub query: Let's first introduce an example: compare whose salary is higher than Abel in the salary table Method 1 (carried out in two steps), the reference code is as follows: SELECT salary FROM employees WHERE last_name = 'Abel'; SELECT last_name,salary FROM employees WHERE salary > 11000; Method ...

data migration target Be able to describe the scheme of project data migrationUnderstand the characteristics of hbaseBe familiar with data packaging and transformation in data migrationBe able to complete the full and incremental migration of article dataBe able to complete the migration of hot article data 1 Why do I need automatic synchro ...

catalogue 1, Environment: 2, Modify case 2.1 modify my CNF (invalid): 2.2docker specifies -- lower case table names = 1 (invalid in specific cases): 2.3 solutions 3, Reference link 1, Environment: centos7,docker 17.12.1-ce,mysql 8.0.21 The mysql command of docker installation: docker run --name mysql --restart=always \     -v /home ...

Differences between MariaDB database and Mysql database mariadb and MySQL belong to the same kind of database management system. However, mariadb and MySQL are different in the scope and purpose of use. Their main functions are to obtain the GPL license through the maintenance of the open source community. In terms of relationship, mariadb bel ...

1, HTML+CSS 2, JavaScript 3, JQuery, BootStrap framework 4, XML 5, Web overview and Tomcat server 5.1 preparation before using tomcat Install and configure jdkDownload and unzip TomcatConfigure environment variables Variable name: CATALINA_HOME Variable value: path just installed 5.2 directory structure of Tomcat Directory nameeffectbin ...

Create advanced join This chapter will explain some other join types (including their meaning and usage), and introduce how to use table aliases and aggregation functions for the joined tables. Use table alias Chapter 10( MySQL must know and know -- Chapter 10 creating calculation fields )Describes how to use aliases to reference table colum ...

Basic part of golang: Go cannot download and install git plug-in because the ip address of go agent cannot be accessed. You can change the following address: Proxy is used by default golang. Org, not accessible at home  go>go get -u github.com/go-sql-driver/mysql  go>go env -w GOPROXY=https://goproxy.cn goweb part: Four link ...