MySQL

Add when building a tableDROP TABLE IF EXISTS' student ';CREATE TABLE' student ' (' stu_id ' )int( One) not NULLauto_increment, ' name 'varchar(255)DEFAULT NULL, PRIMARY KEY(' stu_id '),UNIQUE KEY' Uk_student_name ' (' name ')) ENGINE=InnoDB

1, for some already exist the joint primary key, first delete.Alter Table Drop Primary key;2. Then add the ID to the first row of the table with the name pk_idAlter Table Add bigint (notnullprimarykey first;3. If you want to add a self-increment ID

As the following table structure:CREATE TABLE' trade_order ' (' order_id ' )bigint( -) unsigned not NULLAuto_increment COMMENT'Order Number', ' Total_price 'bigint( -)DEFAULT NULLCOMMENT'Order Total Price', ' Item_name 'varchar( -)DEFAULT

With the accumulation of data, slowly some of our bad habits will be exposed in the system, the efficiency of the program execution is low, the user experience is reduced, if we do not take some measures, then users will be lost.Improving the

One: Simple use of MySQL1. Today to record common SQL commandsView Gallery show databases;view table show tables;Enter library use library name;Create a new library create database name;Create a new table the CREATE table library name. Table Name

Select *  from  (  select  c.ordernumber,   c.name as equipmentname,    A. *,   d.starttime, d.endtime,  (select DateDiff (D.starttime, D.endtime)) as lev ,  case (select DateDiff (D.starttime, d.endtime))   When (select DateDiff (D.starttime,

#python3 connecting MySQL instancesImportPymysql"""Import connection MySQL required package, do not install pymysql need to install using command line switch to python installation path under Scripts subdirectory installation (pip install pymysql)"""

Read Catalogue An introduction Two Insert data inserts Three Update data updates Four delete data deletes Five query data Select Six Rights Management An introductionMySQL Data manipulation: DML======================

Degree from strong to weak1. DROP table TB Drop Delete table directly, no way back 2, truncate (table) TB Delete all data in the table, cannot be used with where 3, delete from TB (where) deleted The difference between the data in a table (a row can

The previous article introduced the manual compilation installation of Apache, this article will continue the previous article that describes how to compile and install MySQL.-Second, compile and install MYCQL1. First unzip the MySQL file to the/opt

ObjectiveA simple experience for beginners only.Prerequisite: MySQL has turned on the Binlog log feature. Can self-Baidu, recommended address--------->windows How to turn on the MySQL log functionExperience Goal: Add a new piece of data to the

Lamp Architecture IntroductionLAMP是Linux apache MySQL php的简写，即可吧apache MySQL和PHP安装在Linux系统上，组成一个坏境来运行PHP的脚本语言，通常是网站。Linux是操作系统apache提供web的一个软件MySQL 存储的一个软件，数据库PHP 脚本语言 三个角色可以在一台机器，也可以分开。不过 MySQL和PHP要在一起。 For example, if you point a picture

db.url=jdbc:mysql://192.168.0.149:3306/pack_platform_dev?useunicode=true&characterencoding=utf-8& Zerodatetimebehavior=converttonull&transformedbitisboolean=true&usessl=falseURL input in db Config file? The following stringMySQL Insert data will

When we use MySQL, we often need to change the root user password for different reasons, this blog mainly describes several ways to modify the root user password. Before the root password is set: How to SET the password command:mysql -u

First, meaningUnion: Merging, combining, merging multiple query results into one resultSecond, the grammarQuery Statement 1 Union "all" query Statement 2 Union "all" ...Third, significance1. Split a more complex query statement into multiple

Tag: Equals condition database design shows Ash SQ nbsp execution InfoIndexBasic concepts of indexingYou can understand the index as a special kind of directory, its existence is convenient for us to quickly query data.I. Classification of the index

There are two main ways to use MySQL for Python operations: Native Module Pymsql ORM Framework Sqlachemy Use action1. Execute SQLImportPymysql#Create a connection, connect to the databaseconn = Pymysql.connect (host ='localhost',

1. Need MySQL driver pack: Mysql-connector-java-5.1.7-bin.jar2.public static void Main (string[] args) {try {Class.forName ("Com.mysql.jdbc.Driver");Connection connect = drivermanager.getconnection ("Jdbc:mysql://172.16.1.23:3306/jmuv3", "root", "123

EmmmmmOne of my friends said 11 o'clock this evening that his database was deleted. was deleted yesterday. I'm on the day. MMP the database does not do backup??????????What FuckThen log on to the server and see.See there's another April 22. Then

MySQL Log management1: Open Binlog Log2: Read Binlog log3: Recover data with binlog logs.a binlog log is generated #vim /etc/my.cnf log-bin=/var/lib/mysql-bin/slave2 server-id=2 //mysql5.7版本以上要写 # mkdir /var/lib/mysql-bin # chown