MySQL

Mysql Performance Optimization analysis ideas:SQL query optimization and index; database table structure; server-level optimization (System configuration; hardware). (one, use index)Indexes are the most common and efficient way to optimize queries,

MySQL high can be implemented in three ways: multi-master mode (Multi master MySQL), MHA (master higher availability) and Galera Cluster:wresp First, MHA? Monitoring the main node, can realize automatic failover to other slave nodes, by

The creation of the index can be done in the CREATE TABLE statement, or you can add indexes to the table by using the CREATE INDEX or ALTER TABLE alone. Deleting an index can be accomplished using ALTER TABLE or the DROP INDEX statement.(1) Create

About MySQL deleting data after the physical space is not released OPTIMIZE TABLE When you delete a large amount of data in your library, you may find that the data file size is not reduced. This is caused by a fragment left in the data file after

MySQL User management Create a user and authorize login Grant all on * * to ' user1 ' @ ' 127.0.0.1 ' identified by ' 123456 ';第一个*表示db_name；第二个*表示tb_name指定其来源IP127.0.0.1（只可通过此IP登录）也可以使用通配符%，代表所有IPidentified by设置密码[[email protected] ~]

Official Installation Instruction manual:Https://dev.mysql.com/doc/refman/8.0/en/windows-install-archive.html Extract The main archive to the desired install directory "unzip to local directory"Optional: Also extract the Debug-test archive

Mysql>MySQL> UseInformation_schema;/*switch to INFORMATION_SCHEMA data*/ Databasechanged MySQL>MySQL> SelectConcatround(sum(Data_length/1024x768/1024x768),2),'MB') asData fromTables/*querying all data sizes*/ +----------+ |Data| +---------

Transferred from: Https://www.jianshu.com/p/15a557ac43d91. Connect to MySQLFirst step, create a new ASP. NET Core ProjectNew ProjectThis routine is a simple demonstration of the connection between the two databases, creating a new default Webapi

#encoding =utf-8 Import MySQLdb Class Sjb_data (): def __init__ (self): Self.url = URL def MySQL (self,sql): db = MySQLdb.connect (host= ' IP address ', port = 3306,user=r ' user name ', passwd= ' password ', db = ' database name ', charset=

1. Check if MySQL is installedCheck to see if MySQL is installed before installing it.If so, execute # rpm-e MySQL or # rpm-e--nodeps mysql Delete.2. Installation via YMLEnter # Yum list First | grep mysql command to view the downloadable version of

First, install MARIADB database on CENTOS7A. InstallationYum-y Install mariadb Mariadb-serverB. StartSystemctl Start mariadbC. System on self-bootingSystemctl Enable MARIADBD. Next mariadb simple configuration (can set the root user's

1: View the storage engine information for MySQL1.1 Use the show Engines command.Mysql> show engines;+--------------------+---------+----------------------------------------------------------------+-------------- +------+------------+| Engine |

Date typeIf you want to use the date, it is usually represented by date.It is usually expressed in datetime if it is to be used to denote a month or a day.It is usually represented by time if it is used only to represent seconds and

First, create a user:Mysql>create user ' username ' @ ' host ' identified by ' password ';User name created by usernamehost specifies on which host the user can log on, if localhost is available to the local user, and if you want the user to be able

CentOS 7 installation MySql1. Download MySQL repo source$ wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm2. Install the MYSQL-COMMUNITY-RELEASE-EL7-5.NOARCH.RPM package$ sudo rpm -ivh mysql-community-release-el7-5.noarch.rpmAfter

Mysqldump is commonly used in MySQL database logical backups.1. Various usage instructionsA. The simplest usage:Mysqldump-uroot-ppassword [database name] > [dump file]The above command backs up the specified database to a dump file (dump file), such

Select Curdate (); --Get the current dateSelect Last_day (Curdate ()); --Gets the last day of the month (based on the current date).Select Date_add (Curdate (), Interval-day (Curdate ()) +1 day); --Get the first day of the month (based on the

Case: The bank's database stores the user's account information table, when user A wants user B to transfer, under normal circumstances, the balance of a account is reduced, the balance of the B account is increased, but for some reason (such as

ORDER BY keyword optimization 1 try to sort by using the index method, avoiding sorting using the Filesort method. 2. MySQL supports two sorting methods, Filesort and Index,index, which refer to the MySQL scan index itself to complete the sorting.

Requirements Description :In the process of using MySQL, you need to calculate the date, for example, a date plus a few days, a few hours, etc.In this record, the use of the Date_add () function.Operation Process :Date_add () function