MySQL

In the use of the database, it is often necessary to query records by a specified date, in order to facilitate statistics, and in the database, there are many stored in the timestamp,There is also a direct deposit date, the query may not be so good

The delete and truncate differences are as follows:One, flexibility: Delete can conditionally delete data, and truncate can only delete all the data of the table;Delete from Table_test where ...TRUNCATE TABLE Table_testSecond, efficiency: delete

1. Unified character encodingEmphasis: Comments in the configuration file can have Chinese, but the configuration item cannot appear in Chinesemysql> \s # view character encoding# 1. Under MySQL's decompression directory, create a new My.ini, and

Server_audit is a built-in MARIADB audit plugin that works equally well in MySQL and is used primarily to record user actions1. Installation:通过show variables like

First create a tableCREATE TABLE classmate ( ID int, CNAME VARCHAR (5), age INT, math double, 中文版 double, Nature DOUBLE);Fill in the table with the dataINSERT into classmate values (1, ' Wang San ', 12,34,55,12), insert into classmate

MySQL Master-Slave introduction MySQL master-slave is also called replication, AB replication. Simply speaking is a and b two machines from the back, write the data on a, the other B will follow the writing data, both data real-time

1. Installing Mysql-serversudo apt-get install Mysql-serverEnter Y, enter. Wait for download, installappears, you need to set the MySQL password.Enter password, return, pop Up confirmation dialog box,Enter the password again. Perform the subsequent

Making MySQL software into a system service3, the MYSQLD software into a system service note: Before making mysqld turn off C:\Windows\system32>Tasklist|findstr mysqld Mysqld.exe8372Console2 454,916K C:\Windows\system32>Taskkill/F/Pid8372success:

First, check the environment# Toggle Root PermissionsSu Root# check if MySQL rpm-qa|grep mysql # has been installed remove all MySQL yum-y remove mysql*1. Upload files to software directory, unzip and modify the folder name to MySQL2. Create user

1. VI/ETC/MY.CNF, add in [mysqld]Skip-grant-tablesFor example:[Mysqld]Skip-grant-tablesDatadir=/var/lib/mysqlSocket=/var/lib/mysql/mysql.sock2. Restart MySQLService MySQL Restart3. Login with user without passwordMysql-uroot-p (Direct click to enter,

Connection poolThe go language comes with a database connection pool, which can be used directly and conveniently.func init() { db, _ = sql.Open("mysql", "root:[email protected](127.0.0.1:3306)/betting?charset=utf8") // 设置最大打开的连接数，默认值为0表示不限制。

1. Union merging of two or more SELECT statements2.year (now ())-year (sbirthday) Get current Age3.order by sort default positive order desc reverse4.group by grouping having a conditional judgment on group by data onlyCOUNT (*): Counts the number

Linux installation MySQLDatabase System1, uninstall the original MySQL (rpm-e mysql--nodeps)2. installation MySQL before, you need to install a software development package, and if you check "software development" when installing the operating

2.1 Database and SQL conceptsA database ( Database ) is a warehouse that organizes, stores, and manages data in accordance with its structure, which has been generated more than 60 years ago. With the development of information technology and market,

MARIADB is installed by default in CentOS, this is the branch of MySQL, but in order to need, it is necessary to install MySQL in the system, and after the installation is complete, you can overwrite the mariadb directly.1 Download and install the

#!/bin/bashDbname= User name #DB数据库Backup_dir=/data/mysqlbackup/databackup #备份目录dbrootpwd= Password #DB用户名root密码:Expired_days=7 #BD备份存储7天logfile= $backup _dir/db.log #日志文件dumpfile= $backup _dir/db_lelaohui_$ (date +%y%m%d_%h). SQL #备份数据库文件newfile=

In the daily operation and maintenance of MySQL database, it is necessary to control the permissions of the business sub account.Business is basically divided into read accounts and write accounts two accounts, so can be organized into fixed stored

First, IntroductionMySQL Data manipulation: DML Database Manipulation languageIn MySQL management software, you can use the DML language in SQL statements to implement data manipulation, includingInserting data by using insertUpdate to implement

in Linux sometimes installing MySQL will appear without root user condition, or the root account is deleted from the Mysql.user table mistakenly, so that many permissions can not be controlled. The workaround is to recreate the root user and grant

Grammar:WHERE column inch (value1,value2,...) WHERE column not inch (Value1,value2,...)1, in the back is the recordset, such as:Select * from Table where Uname in (select uname from userExample:SELECT * FROM article WHERE uid in (SELECT