MySQL

The explain command is the first recommended command to address database performance, and most performance issues can be easily resolved with this command, explain can be used to see how SQL statements are executed, to help select better indexes

For MySQL internal connections, outer connections, cross connections1. Internal connection : Combine the rows in two tables that meet the join criteria as a result set------innerSyntax: Select column 1, column 2, column n from table one inner join

First, the relevant instructionsThe production line uses the Zabbix 2.4.5 to monitor all business and system networks, of course, also need to monitor the MySQL database related information, Zabbix with the MySQL monitoring template can monitor

First, installation reprint: http://blog.csdn.net/chenpy/article/details/50344085 1. Upgrade Apt-get Apt-get Update If it appearsIf you are not the root user, you will need to use the sudo command sudo apt-get update

Now to do a data migration, you need to update the relevant data, you need to update in MySQL, you cannot use the updated table as the query table.To summarize:One: When a single table is updatedFor example: Update customer Set category = 1 WHERE

1. Add primary key (primary key index)Mysql>alter TABLE ' table_name ' ADD PRIMARY KEY (' column ')2. Add unique (unique index)Mysql>alter TABLE ' table_name ' ADD UNIQUE (' Column ')3. Add index (normal index)Mysql>alter TABLE ' table_name ' ADD

The previous article has been involved, here as a summary of the reorganization.First, function 1, arithmetic functionNUMERIC is a data type that is supported by most DBMS, specifying the size of a numeric value by Numberic (the total number of

Docker MySQL stores data in a local directory, and it's simple to map a local directory to a container1. Plus-v parameter$ docker run-d-e mysql_root_password=admin --name MYSQL -v /data/mysql/data:/var/lib/mysql -P 3306: 3306 MySQLYou can also

First, the business 1. Submit 2. Rollback 3. Acid characteristics Second, the View 1. Create a View 2. Delete View 3. Update view 4. Using views Third, sub-query 1.

ObjectiveChoice is a brand-new beginning, the choice of towering cliff will need to have " long road its repair far, I will go up and down and seek " the belief; choose wave swell rolling sea will need to have "straight hanging Yun fan ji hai" lofty

First, the basic principle of replication1. Slave will read binlog from Master for data synchronization2. Step + schematic diagram　　　　Ii. Basic principles of replication1. Only one master per slave2, each slave can only have a unique server ID3.

This article refers to the experimental building of the SELECT statement in detail with their own operating part of the written.Note: in most systems, SQL statements are case-insensitive, but for rigorous and easy-to-distinguish reserved words and

Under Window1. Export the entire databaseMysqldump-u user name-p database name > exported file nameMysqldump-u dbuser-p dbname > Dbname.sql2. Export a tableMysqldump-u user name-P database name Table name > exported file nameMysqldump-u dbuser-p

Create a MySQL DatabaseCREATE DATABASE IF not EXISTS DEFAULT CHARSET UTF8 COLLATE utf8_general_ci;Creating MySQL data tablesDrop Table if exists' table_name ';Create Table if not exists' table_name ' (IDintAuto_incrementPrimary KeyComment'PRIMARY

MySQL master-slave configuration for read-write separationLarge web site in order to soft solution a large number of concurrent access, in addition to the site to achieve distributed load balancing, far from enough. To the data service layer, the

"Three major paradigms of database design"1. First paradigm (1NF): Each column in the data table must be the smallest unit that cannot be split. That is to ensure the atomicity of each column.For example: UserInfo: ' Shandong province Yantai 18865518

Import the provided Websites table SQL file websites.sql into the MySQL database.Problem found:Found in the local database path, yes: C:\ProgramData\MySQL\MySQL Server 5.6\data This is ProgramData, not program Files.and the MySQL installation

Multi-Table query and Table query /*Create a one-to-many tableMain table: Product category Table categoryFrom table: Product table productsProducts uses the primary key in category as the foreign key*/-- Create a product category table category:

Turn: What is the difference between MySQL and Oracle? 1. Oracle is a large database, while Mysql is a small and medium-sized database. The market share of Oracle is 40%. Mysql is only about 20%. At the same time, Mysql is open source and Oracle is

When mysql imports the database, the error 1840 solution is returned. mysql1840 1. symptom When mysql imports a database using an SQL file, the ERROR 1840 (HY000) at line 24: @ GLOBAL. GTID_PURGED can only be set when @ GLOBAL. GTID_EXECUTED is