MySQL

Let's take a look at how to read these slow query logs.Before you trace a slow query log, you must first ensure that you have a slow query at least once. If you are not able to make one yourself:[Email protected]# mysql-e ' SELECT SLEEP (8);There's

The recent use of free time to read the MySQL must know, for the MySQL foundation to understand more deeply. Before the main use of SQL Server development, so for MySQL do not know too much, feel the same, no need to learn, with the time to check on

First written in front, MyCAT1.4 's alpha version has been released, which fixes a lot of bugs, but also perfected a detail, the previous two blog has made some

MySQL Password management: To modify a user password:(1) Set PASSWORD [for ' user ' @ ' host '] = PASSWORD (' cleartext PASSWORD ');(2) UPDATE mysql.user SET password=password (' Cleart Ext password ') WHERE user= ' USERNAME ' and host= ' Host

Find the highest grades in each sectionCREATE TABLE Grademax (ID int primary KEY auto_increment,Name varchar (20),Subject varchar (20),Grade int);Insert into Grademax (name, subject, Grade) values(' dots ', ' language ', 100),(' Little black ', '

Precautions:1. Import Microsoft.EntityFrameworkCore.Tools and MySql.Data.EntityFrameworkCore with NuGet before use2. DataContext must declare a constructor to accept a Dbcontextoptions must pass it to the DbContext base constructor.3, the

MySQL can go to the official website to download the corresponding version for installation, the version used here is "Mysql-5.5.40-win64.msi";Installation1. Double-click "Mysql-5.5.40-win64.msi" to enter the installation page.There will be a

MySQL index create, view, delete, and use examples1. Create an index:ALTER table is used to create a normal index, a unique index, or a primary key index.ALTER TABLE ADD INDEX index_name (column_list) ALTER TABLE ADD UNIQUE (column_list) ALTER TABLE

Problem: ERROR1045 (28000): Access denied foruser' root ' @' localhost ' (using Password:no)ERROR 1045 (28000): Access denied foruser' root ' @' localhost ' (using Password:yes) Workaround:1. Enter/etcCD/ETC;2. Edit the MySQL configuration file (if

The syntax described below, when the usage scenario is to move a node in the tree, modifies the node and all parent nodes (Parentids) of its child nodes.Update trainstaff_dept Set parentids = replace (Parentids,#{oldpid},#{newpid}) where Companyid=#{

The Ysql index is used to quickly look for records with specific values, and all MySQL indexes are saved as B-trees. If there is no index, MySQL must start scanning all records of the entire table from the first record until it finds a record that

/* ******************************************************************************** * BuildRoot mariadb Alternative to MySQL * Description: * in the process of MySQL, found that the original MySQL did not appear the MARIADB

querying data for the current weekSELECT Name,submittime from the Enterprise WHERE Yearweek (Date_format (submittime, '%y-%m-%d ')) = Yearweek (now ());query last week's dataSELECT Name,submittime from the Enterprise WHERE Yearweek (Date_format

Explain:SELECTCase-------------IfWhen the sex= ' 1 ' then ' Male '-------------sex= ' 1 ', the return value ' male 'When the sex= ' 2 ' then ' female '-------------sex= ' 2 ', the return value ' female 'else 0 return ' other '-------------otherEnd---

Detailed analysis of SQL Execution steps and SQL Execution steps Detailed analysis of SQL Execution steps First, let's look at the sequence of statements executed. (8)select (9)distinct A (1)from Ta (3)join Tb (2)on XXX (4)where XXX (5)group by XXX (

Mysql master-slave deployment and mysql master-slave deployment1. installation environment 1. System Environment System IP Host Name Description Server_id Centos6.7 192.168.0.173 Master Database: Master 173

Mysql learning-> DML and DDL statements, mysqldmlddl statements DDL statements: database definition language, which is generally used for database operations, such as create, drop, and alter. DML statement: data operation language, curd

Detailed description of InnoDB parameters, 1. query InnoDB parameters of MySQL 5.5 and comment on the following:[Root @ localhost etc] # grep-I innodb my. cnf; T_innodb; otherwise, slaves may diverge from the master. Uncomment the following if you

The concept of cluster and high availability (HA), clusterha Reposted from: http://www.cnblogs.com/blackwizard2016/p/5143816.html, which is used only for learning. 1.1 What isCluster To put it simply,Cluster (ClusterIs a group of computers,They

Mysql-High-Performance Index policy, mysql-High-Performance IndexIndependent index: An independent index means that an index Column cannot be part of an expression or a function parameter. 　　Example 1:SELECT actor_id FROM actor WHERE actor_id + 1 = 5