MySQL

Install MySQL1. Uninstall the old versionUse the following command to check if MySQL Server is installed we found the result:[[email protected] ~]# rpm -qa | grep mysqlmysql-libs-5.1.73-7.el6.x86_64Some words are unloaded by the following commandrpm

Recently, using the latest version of MySQL, 8.0.11 found that the default value of MySQL's log_bin parameter changed to ON. At first, the change was not noticed, resulting in the use of a lot of bin logs, which consumed a lot of disk space.So you

#下载mysql源安装包shell> wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm# install MySQL sourceshell> Yum Localinstall mysql57-community-release-el7-8.noarch.rpmCheck that the MySQL source is installed successfullyshell> Yum

The UNION is used to combine the result set of two or more SELECT statements and eliminate any duplicate rows in the table.The SELECT statement inside the UNION must have the same number of columns, and the column must have a similar data type.Also,

When executing the script, you need to keep up with the database name you need to back up, as follows#!/bin/bash#auto backup MySQL#20180522 by Jzh##################################Define PATH definition Variableback_dir=/data/backup/mysql/' Date +%y-

In the MySQL database, the most commonly used engines are 2: InnoDB and Myiasm.First of all:1. Brief introduction of these two engines, and how to choose.2. What are the data structures used by these two engines?1.A.innodb engine, the InnoDB engine

Selection of data typesSelect the appropriate data type for the fields in the table :When a column can select more than one data type, it should take precedence over the number type, followed by the date or binary type,Finally, the character type.

Basic Introduction to MySQL (This article is based on a Linux system):MySQL is a database management system, is a typical relational database management system. The database is small, fast, and inexpensive, and the source code is open, so small and

Yum installation linux+apache+mysql+php Configuring the Yum Sourcewget -o/etc/Yumrepos.d/centos-base.repo http://mirrors.aliyun.com/repo/ Centos-7.repoYuminstall epel--uvh https://mirror.webtatic.com/yum/ el7/epel-release.rpm-uvh https://mirror.

Reasons and solutions of missing Libstdc++.so.6 libraryWorkaround:First, the installation library1. See which installation package contains the library : Yum provides libstdc++.so.6libstdc++-4.4.7-4.el6.i6862. Follow the prompts to install the

In the morning, Red came to ask me that a function of the site has gone, looked at the database, a table is missing. Okay, in the heart, MMP, start recovering data.Environment: A full library backup restores a table1.1 Viewing Backup Data[Email

I don't expect to be an expert DBA, but when I optimize MySQL, I'm advocating the 80/20 principle, which makes it clear that by simply tweaking some configurations, you can squeeze up to 80% performance gains. Especially at a moment when server

5 after the installation is successful, start the MySQL times error:System error 2, the specified file could not be found. Cause: Some systems installed MySQL did not uninstall cleanly, or the system comes with a lite version of MySQL caused the

Create a new event in the event SQLyog a database and write the code:DELIMITER $ $ALTER definer= ' root ' @ '% ' EVENT ' 0 ' on SCHEDULE every HOUR starts ' 2018-04-18 00:00:00 ' ENDS ' 2028-12-31 00: 00:00 ' On completion no PRESERVE ENABLE do

SELECT statementRetrieving a single columnRetrieving multiple columnsRetrieving all ColumnsRetrieving a different rowLimit resultsUsing a fully qualified table name1.select statementsUsing Select to retrieve table data, you must give at least two

The difference between Drop,delete and truncate:Priority: Drop > Truncate > DeleteTRUNCATE by row Delete does not log the delete operation record into the journal Save (unrecoverable)Delete all delete the data in the table and can record the

Data query StatementsSelect column name, column name, column name ... from table name [where condition]The column name is the name of the field, note that the last column name does not have a comma, the condition after the table name can be added

inserting data using T-SQL inserting data using Insert1 inserting a row of data INSERT into table name ( column list ) VALUES ( List of values )Into can be omittedList of column names can omit "NOTE" Insert all columns at one time if

Grades Table:Student table:Using an inline query in a federated query inner join similar intersection:2, query all scores of the specified userSelect student.name,grades.* from Student,grades where student.id=grades.id and Student.name= ' AAA ';The

MySQL database managementMySQL database version of my experiment: 5.5.56-MARIADB MariaDB Server operating system: centos7.51. Create a databaseMariaDB [(None)]> CREATE database test1;2. View all databasesMariaDB [(None)]> show Databases;　　　　+--------