MySQL

What is a database? A database is a warehouse that organizes, stores, and manages data according to its structure, and each database has one or more different APIs for creatingTo build, access, manage, search, and replicate saved data.We can also

First, why the query slowNetwork, CPU calculation, generated statistics, execution technology, lock wait, io wait, etc.Second, slow query optimization access to inefficient query processing methods: Confirm that you have accessed too many

Linux under mysql forgot root password can skip safe mode into mysql change root password;First turn off the MySQL services,serviceMySQL stopThen find the mysql configuration file my.cnf,In the mysqld configuration, add:skip-grant-tables;Restart

If the setting in an item is varchar (50) Then of course the English is 50 then the Chinese is utf-8 3 bytes So, is this varchar (50) only able to save 16 characters? No, this is the case with MySQL, but not after 5.0.MySQL varchar (50) Both Chinese

When we write SQL, we often use in,in followed by a list of constants, such as ID. Some say in is very efficient, and some say it is very low, some say in can use index, others say in cannot use index ...What kind of a situation is it? We analyze

example, MySQL database backup script.Vim mysql.sh#!/bin/Bashday= ' Date +%y-%m-%d '//date is displayed and given the day variableSize= ' Du-sh/var/lib/mysql//check the size of MySQL and assign a variable sizeEcho"Date:

First, why the query slowNetwork, CPU calculation, generated statistics, execution technology, lock wait, io wait, etc.Second, slow query optimization access to inefficient query processing methods: Confirm that you have accessed too many

After each interview, we decided to change the former. The fact remains the same as the fat men who swore to eat the last meal. Whether this is a three-minute heat, but at least I'm starting. MySQL engine Speaking of MySQL engine, I also think of

Unzip the downloaded compressed packageCopy a My-default.ini change name to My.ini as MySQL configuration fileOpen My.ini Modify configuration fileThe default original file is# for advice The change settings see#

The regular expression function is really powerful, the day dedicated to learning, here is temporarily used in MySQL query. Regular expressions are powerful and flexible and can be applied to very complex queries. Options

Database additions and deletions are to be mastered. This part will take a look at the previous 3 relatively simple parts, increase, delete, change. Inserting data Insert data for all fields of a table INSERT INTO table_name (column_list) values

The Group_concat () function in MySQL is primarily used to process a one-to-many query result, which is typically used in conjunction with GROUP by.Grammar:1Group_concat ([DISTINCT]Expr[, expr ...]2 3 [ORDER by {unsigned_integer |

1. First unzip the MySQL package, then add the environment variable path (D:\mysql-5.7.11\bin)2, modify D:\mysql-5.7.11\my-default.ini? Configuration items for files? # basedir = D:\mysql-5.7.11# DataDir = D:\mysql-5.7.11\data# port = 33063, CMD

Do not stop to do MySQL master-slave synchronization, you can use mysqldump, but this low efficiency, the use of xtrabackup to achieve this, high efficiency!One Xtrabackup installation:Yum-y Install Perl perl-devel libaio libaio-devel

1. Edit the My.cnf file:sudo vi/etc/mysql/my.cnf 2, comment out the binding address line or modify to specify ip#bind-address = 127.0.0.1 3, login mysql:mysql-uroot-p password 4, add root user access to the Gran T all privileges on * * to ' root ' @

Before modifying the local root user password of the database, I found that the password of the root user of my remote connection did not change, then looked up and found that the original two root is not the same user (Khan. ）So Lenovo to the

Change the MySQL file every 0.1 seconds and flash to see the order of MySQL processing when SQL executes.Watch-n 0.1-d stat/var/lib/mysql/ib_logfile0/var/lib/mysql/ib_logfile1/var/lib/mysql/ibdata1I understand the order of execution: (also missing

Centos7 under yum install MySQLCentOS 7 's Yum source does not appear to be properly installed when MySQL mysql-sever file, need to go to the official web download#wgethttp//dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm# RPM-IVH

Material is from the textbook down, the main content is practice examples, in writing blog post learning command line, of course, I hope this blog post can help others learn mysq database commandSelect statement to select specific rows and columns

* Database concept:* Database-databases* One database contains multiple tables* Table-Tables* One table contains multiple rows and multiple columns* Row-line* One line represents a single piece of data* Column-Columns* One column represents a single