MySQL

1. In Linux, detect if MySQL is installed:PS: Start MySQL service with Super Administrator2. Log in to the MySQL server, root is the user name, and the password is empty.3. View the database4. Connect to the database5. View the table6. Exit----------

1. Install the mysql5.6 dependency Pack [[email protected] src]# yum-y install make gcc-c++ cmake bison-devel ncurses-devel libaio[[email& Nbsp;protected] src]# yum install Libaio libaio-devel-y[[email protected] src]# yum install net-tools-y2.

In real-world projects, paging queries are commonplace, even unavoidable. It is difficult to meet the effect of efficiency when the data volume is usually low. But when the amount of data is large, a normal paging SQL can make you nauseous.Our

Server basic Environment:Two centos6.4, iptables diabled, SELinux disabledThe hosts analysis of the two units#yum Install MYSQL-Y//This must be installed, MySQL and mysqldump command all depend on itMySQL installation (two identical

Difference:1. InnoDB support transactions, MyISAM is not supported, for INNODB each SQL language is encapsulated as a transaction by default, auto-commit, which affects speed, so it is better to put multiple SQL language between Begin and commit,

1.sql Statement Classification:DQL Statement data Query Language SelectDML statement Data manipulation Language Insert Delete updateDDL statement Data Definition language Create drop alterTCL Statement Transaction Control Language commit rollback2.

1) Basic EnquirySELECT stuname,id,age,sex,gradename from T_student;SELECT * from T_student;SELECT stuname,gradename from T_student;2) When a query satisfies a certain condition, it mainly uses the where1. Basic conditions　　SELECT * from T_student

1.in and not in sub-query optimizationsNot in is not a hit index, so the following subquery performance is low.If it is a deterministic and limited collection , you can use it. such as in (0,1,2).Replace with exists or notexists select * test1

To view the RPM packages installed in the systemRpm-qa | grep MySQLUninstall your own MySQLrpm-e--nodeps *Unzip MySQLTAR-XVF Mysql-5.7.18-1.el7.x86_64.rpm-bundle.tarInstallation Ordermysql-community-common-5.7.18-1.el7.x86_64.rpmmysql-community-libs-

I. Index 1. Index Introduction 2. Index type 　1. BTREE type 　　is a kind of index value according to a certain algorithm, stored in a tree-shaped data structure. (e.g.:) For example, is a B + tree, the definition of B + tree can be

First you have to have a ballpark understanding of MySQL.For example: How to install, use the basic syntax, test the installation can be successful, and successful after the simple database, operation (increase and deletion) ...Here is the business

1. Download: Http://dev.mysql.com/downloads/mysql/5.6.html#downloadsDownload version: I choose here 5.6.33, General edition, Linux under 64-bitYou can also directly copy the 64-bit, download by command: wget http://dev.mysql.com/get/Downloads/MySQL-5

1. Download MySQL Installer2. InstallationKeep the next until finish.3. Configuration at the time of installationOnce the installation is complete, select Start configuration now.Select Standard ConfigurationTick install MySQL service and start

1.Com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException:Unknown columnCause: Sting type does not have single quotation marks2.Duplicate entry ' 1 ' for key ' PRIMARY 'Cause, the primary key value is present or chaotic, you need to delete the

MySQL TransactionMySQL transaction is mainly used to deal with large-scale and high-complexity data.For example, in a personnel management system, you delete a person, you need to delete the basic information of the person, but also to delete the

One. Isolation level:The SQL standard defines 4 isolation levels, including specific rules that define which changes within and outside a transaction are visible and which are not.Low-level isolation levels generally support higher concurrency

The most recent project requires a lot of SQL statements to be written. Involves a lot of time-related processing, now do a simple summary.1. Time format : In this project, perhaps the database table structure created by different people, the format

Question of the week number1 calculation date is weekThis seems like a simple question, and you can use MySQL built-in functions to calculate(1) weekday (date) whose return value is 0-6, 0 for Monday, 6 for Sunday;(2) DayOfWeek (date) whose return

first, the demandTo update the Status field for data that begins with Base_info.name to Wl_ to 2Second, the implementationUpdate Base_infoSet a.status=2Where (select id from base_info where name is like '%xx% ')when executing, prompt 1093

Transfer from https://www.cnblogs.com/wsl222000/p/5445768.html1. Installing the mysql-5.5 Yum sourceRPM-IVH http://repo.mysql.com/yum/mysql-5.5-community/el/6/x86_64/mysql-community-release-el6-5.noarch.rpmTo install MySQL5.6, you can