MySQL

In MySQL, the data n in int (n) parentheses, no matter how much it is written, is a space of 4 bytes and can store up to 10 digits. n does not represent the number of digits that can be saved, and the display width m is independent of the space

In the maintenance process, we are more tangled in the format of the Time field, I combed today, MySQL other common syntax and oralce basic similar (including comments and so on with the same as Oracle), the difference is the same date type.The time

Recently there is a system database weekend always alarm, CPU utilization of more than 90%, started by the development side to follow up processing, I also did not participate, later found no progress on the login to see the next, and then a partial

First, IntroductionMySQL currently has the following types of indexes:1. General Index2. Unique index3. Primary KEY index4. Combined Index5. Full-Text IndexingSecond, the statementCREATE TABLE table_name[col_name Data

11.1 Lamp architecture is the shorthand for Linux Apache MySQL PHP, which is to install Apache MySQL PHP on a Linux system to form an environment to run the PHP languageApache (httpd) and PHP are a whole (PHP is combined in the form of a module with

**************************************************************************************************MySQL 5.7 Compilation process**************************************************************************************************1. Installing dependent

**************************************************************************************************MySQL 5.5 Compilation**************************************************************************************************1. Install the compilation

  Method 1: Use the Set password command first log in to MySQL. format:mysql> Set password for user name @localhost = password (' new password ');example:mysql> set password for [email protected] = password (' 123 '); Method 2: Use Mysqladmin Format:

The first chapter data backup and Import Export1.1. Introduction to basic concept of backup1.2, Mysqldump detailed1.3, Mydumper Analysis1.4. mysql Physical backup basic operation1.5. Understanding Mysqlpump Tools1.6. Data import and Export1.7. Flash

1. Syntax: Select query list from table name Where2, filter criteria classification:(1) Filter by conditional expressionSimple conditional operators:>, , >=, (2) Filter by logical expressionLogical operators: Used to join conditional expressions&&, |

MySQL View data 1, show all current database namesshow databases;2. Display the current databaseSelect Database ();3. Display all tables of the current databaseShow tables;4. Query all records in the table (two ways)(1) In the user table the current

MySQL Delete data 1, delete haha databasedrop database name;2, delete the table (two ways)(1) Delete the drop table name directly in the current path of the user table;(2) Do not delete the table in the current User table path and specify the path

MySQL Add data 1, new database userNew Feiyu database user allows login at all IP addressesmysql> create user ' Feiyu ' @ '% ' identified by ' 123 ';New Guest database user allows all addresses to be logged in the 192.168.1 network segmentmysql>

MySQL website download rpm package, I choose the latest version of MySQL 8.0Install RPM Package:rpm -uvh platform-and-version-specific-package-name. RPM Download MySQL:yum install mysql-server (Note this is-server)Start Services after installation:

The basic problem with replication is to keep one server's data synchronized with other servers. Data from one master server can be synchronized to multiple slave servers. And from the server can also be configured as the main library of another

SELECT m.content,o.order_price,o.id,m.id from INNERJOIN on m.link_id=o.idChange the amount of content into Order_price1. Get the amountSELECT substring_index (content,' paid ￥',-1) from WHERE id=1096; -- 1000.00 "}2. Get the last two

Basic Environment1.OS version Centos72.mariadb-5.5.56[email protected] ~]# Yum install-y mariadbLoaded plugins: FastestmirrorBase | 3.6 KB 00:00:00elasticsearch-2.x | 2.9 KB 00:00:04Epel/x86_64/metalink | 4.8 KB 00:00:00Epel | 4.7 KB 00:00:00Extras |

Combine a WHERE clause1.1 AND operator1.2 Or operator1.3 Calculation Order In operator Not operator 1.1 AND operatorMariaDB [test]> Select Id,age,province-From user-Where age +----+------+----------+| ID | Age | Province |+----+----

The storage engine is located on the third tier of MySQL's logical architecture, responsible for storing and extracting data from MySQL. There are many MySQL storage engines, and different storage engines have different ways of saving data and

1. Install the MySQL mysql-server and mysql-cilient installation package:Start the depth terminal, enter "sudo apt-get install Mysql-server mysql-cilient" in the terminal and enter the administrator password when "Do you want to continue?" [y/n] "Y"