MySQL

MySQL master-slave replication overview:MySQL master-slave replication, can achieve read-write separation and multiple automatic backup, improve database load capacity and security. Such as:　　　　　　　　When the Web server writes data to the MySQL

The table reads as follows:1, implement batch import Word document, take the number of the document title as number2, in addition to the above to check the contents of the hook should be matched out of the storage, the other contents of all direct

Table lock MyISAM engine (table level)Read lock, can not write, write lock a table, other session can not read and write a tableRead lock session-1 can only check a table, can not check other B tableSession-2 write blocking, can query all

Always small table drive large table (small Data driven big data)In in1 form b wehre b.id=a.id) If the A table data is less than the B table data with exists ORDER by using the indexTwo ways to sort Mysql: Sort files, scan ordered index sortMYSQL

MySQL Error 1045 (28000): Wrong resolutionListen to the Voice | Browse:54286 | Updated: 2018-02-23 14:34 | Tags:mysql 1 2 3 4 5 6 7 Step through ReadingERROR 1045 (28000):

MySQL ifnull function is one of the MySQL control flow functions, he accepts two parameters, if the first parameter is not empty return the first argument, otherwise play the second argument.Two arguments can be literal values, or expressionsIfnull (

The role of the database　　The popular database　　Basic concepts of databasesObjectively, the things that can be described are entities .　　A table is a collection of data , a database is a collection of tables , and a relationship is part of a

1. Optimized query for query cacheMost MySQL servers have query caching turned on, which is one of the most effective ways to improve performance, and this is handled by the MySQL database engine.Some queries do not use caching, such as Curdate (),

Indexes after a single-table range query are invalidatedDouble-table left and right connections to make an index use each otherThree tables using small result sets to drive large table results, first optimize the parentheses inside the SQL, to

I recently encountered a problem with the project is that the database orders need to check their order status regularly, if the time of the Endtime field order status or 2, the order status is modified to 4Find a similar solution on the web.The key

24.1 Database OverviewThe Digital Library (dtabase) is an existential data (Data) of the warehouse, theWarehouse isTechnical Photo OneData structures (data structures are exponentialThe form of a group or a link between data) to organize the

Tag: TE path SQ default system star start password addOne. Open Terminal (alt+ctrl+t):sudo Install mysql-server mysql-clientDuring installation, you will need to enter the root account password, enter the password, wait for the installation to

Rights Management (Root)1. Create an Account# local AccountCreate user ' egon1 ' @ ' localhost ' identified by ' 123 '; # mysql-uegon1-p123# Remote account, client IP (192.168.31.10)Create user ' egon1 ' @ ' 192.168.31.10 ' identified by ' 123 '; #

I. Introduction to MySQL PrivilegesThe simple understanding of MySQL permissions is that MySQL allows you to do what you do best, and you can't cross the border. For example, if you are only allowed to perform a select operation, you cannot perform

Make a backup to another tableSELECT * Into Persons_backup from Persons this way in MySQL run will report undeclared variable errorMySQL does not support, replaceCREATE TABLE Persons_backup (select *from persons)Copy a field from one table to

It is not a problem in MSSQL to use entityframework random ordering (c + = Guid.NewGuid ()), but there is no such function in MySQL,Since the MySQL error does not have this function, just want to create a try, did not expect to really.// CREATE

1. Create a Database: Code created: CREATE DATABASE: Database table name: Whatever you want, just remember it. TestCreate DATABASE test;2. Delete database: Deleted code: Drop DATABASE code: database to delete which database: DB name: Testdrop

Common functionsTotal: Select count as TotalCount from table1Sum: Select SUM (field1) as Sumvalue from table1Average: Select AVG (field1) as Avgvalue from table1Maximum: Select Max (field1) as MaxValue from table1Min: select min (field1) as MinValue

Preliminary understanding of MySQL Basic database language1. Create a MySQL DatabaseCREATE DATABASE database_name;2. Show all MySQL databasesshow databases;3. Use a MySQL databaseUse database_name;4. Delete a MySQL databaseDROP DATABASE

Locate the MySQL 5.6 configuration file, my.cnf (Windows is My.ini), and add the following lines under [Mysqld]:long_query_time=2Slow_query_log=1Slow_query_log_file=/tmp/slow-query.log (can write absolute path here: D:/www/slow-query.log)Run the