MySQL

1.in and existsin is the appearance and the inner table as a hash connection, and exists is the external loop loop, each loop loop and then query the internal table. The assertion that exists is more efficient than in is inaccurate. The subquery

1. Download the 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 installing this package,

1. Common commands:Install upload download File commandYum Install LrzszInstalling the WebGet toolYum-y Install wget------------------------------------Split Line---------------------------------------------After successfully installing MySQL server

1. Display long as a timeSELECT from_unixtime (1249488000, '%y%m%d ')2. Date format into timestampSELECT unix_timestamp (' 2016-05-14 23:23:00 ');3. Negative time stamp (date before 1970)Date processed 1970 years ago in MySQL (case with negative

DROP FUNCTION IF EXISTSRand_string;delimiter $$CREATE FUNCTIONRand_string (nINT)RETURNS VARCHAR(255)BEGIN DECLAREChars_strvarchar( -)DEFAULT 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'; DECLAREReturn_strvarchar(255)DEFAULT "';

A brief introduction: Today free to work, write a basicTwo purposes: to provide non-DBA universal installation of MySQL 5.7 source package installationThree steps:1 Installing the base environmentYum-y Install gcc-c++ ncurses-devel cmake make perl

1. Install MySQLYum install-y autoconf libaio-devel wgetgroupadd Mysqluseradd-s/sbin/nologin-g MySQL-M MYSQLCD/usr/local/Srcwget HTTp://mirrors.sohu.com/mysql/mysql-5.6/mysql-5.6.36-linux-glibc2.5-x86_64.tar.gzTAR-ZXVF mysql-5.6. $-LINUX-GLIBC2.5-X86

This article takes windows as an example for you to introduce the 4 ways to change the root password of MySQL, you can choose according to their own circumstances, hope to help everyoneMethod 1: Use the Set password command First log in to

Query data: SELECT * from XXX;Example:(1) Select Id,username,password from T_user;(2) Select Id,username,password,gender from t_user where gender = ' male ';(3) Select Id,username,password,gender from t_user where gender is null; Add data: Insert

Note: This article uses the mysql5.5 version as an example. The students who have done database development should not be unfamiliar with view. I have access to the most views of the application scenario has two: 1) for permission issues, in order

Environment IntroductionServer address:192.168.99.122MySQL version: MySQL 5.7Mysql-community-server-5.7.19-1.el7.x86_64Operation Steps#下载安装yum源wget http://repo.mysql.com/mysql57-community-release-el7-11.noarch.rpm#安装源RPM-IVH

Note: This article is the basic knowledge of MySQL summary, a lot of basic points if not enough, also please search by yourself. Subsequent additionsFirst, MySQL IntroductionIntroduction to DatabasesDatabase is a kind of system specialized in

They are stored in different ways and data are retrieved differently.Data retrieval efficiency is: char > VarChar > TextSpace occupancy, it is necessary to specifically analyze the specific situation. 1.char: It is convenient to store the fixed-

1.master ConfigurationServer-id=1log-bin=mysql-binbinlog-do-db=testdatabinlog-ignore-db=mysql2.master Add UsersGrant Replication Slave on * * to ' test ' @ ' 192.168.176.% ' identified by ' 123456 ';3. Check whether the primary database can be

First, log in to MySQL1. Start:MySQL boot file in the/ETC/INIT.D directory, start running the following command/etc/init.d/mysql start2. Stop:/usr/bin/mysqladmin-u root-p shutdown3. Login:MySQL [-u username] [-h host] [-p password] [dbname]Here we

Today, when you are learning SQL statements, you encounter the use of exsits, the following are the topics:Table SchemaStudent (s#,sname,sage,ssex) Student tableCourse (c#,cname,t#) timetableSC (s#,c#,score) score tableTeacher (t#,tname) Teacher

1. Download MySQL from official website :http://dev.mysql.com/downloads/2. Unzip to the directory you want to install (Bo master installation to: D:\mysql)　　Add a new My.ini file and write the following:　　Press CTRL + C to copy the codePress CTRL +

Li Wu:Learn to think more, honouring teachers save Thanksgiving. Leaf See Root 321, rivers with one.Meekness Conscience Lord, willing to do without regrets to the most bitter. Reading exercise strong body and mind, Prudential advised and the line

Solve mysql "Access denied for user 'root' @ 'localhost '" # mysql -uroot -pEnter password:ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO) Update user set host = '%' where user = 'root '; Use the methods described

MaxIdle, MaxActive, maxWait parameters in the connection pool, and maxidlemaxwait Parameters in the connection pool: Name: indicates the name of your connection pool, that is, the address you want to access the connection pool. Auth: indicates the